Shop from a list: unit prices, labels and a food budget
A shopping list ordered by store section with amounts and an already-have column, unit prices compared, labels read in the store, and a weekly food budget set from your own spending first.
- Start here: the essentials
- 1. Shop your kitchen first, then write the list
- 2. Unit price and cost per serving
- 3. Store brands, convenience forms and bulk
- 4. In the store and on the way home
- 5. A weekly food budget
- 6. Food help, for anyone
- 7. Coupons, trip frequency and prices
- 8. See it: Jordan's list
- 9. Practice: one list, one trip, one receipt
- 10. Your kitchen
- 11. Check your work
- 12. Knowledge check and scenario
Start here Essentials
At minimum, make one list from your plan, compare two unit prices, shop from the list once and write the receipt total down. Setting a budget and everything marked Go deeper can wait.
- Make the list from your plan and tick what you already have in the fridge, freezer and cupboard (shop your kitchen first).
- Order it by store section, with the amount and the meals each fresh item is for (the list).
- Compare unit prices for two items you buy often and write the lower one on the list (unit price).
- Shop from the list and get cold food home and put away within 2 hours (getting groceries home).
- Write the receipt total on the spending sheet beside your baseline week (a weekly food budget).
Minimum time: about 30 minutes for the list and the unit prices, plus your usual trip. Done when: the list was used for one trip and the week's total is on the spending sheet.
1. Shop your kitchen first, then write the list Understand
A shopping list made from a plan is the plan's ingredients minus what is already in the house. EPA's Smart Shopping sheet puts that in four words, "shop your kitchen first", and gives a list with three columns: the food item, the amount needed and what you already have (EPA, Smart Shopping: Shop with Meals in Mind). Its own example row is salad greens: needed, lunch for a week; already have, enough for one lunch. So the list asks for six lunches of greens, not seven.
The already-have column is where Kitchen inventory and The weekly plan pay off. The freezer list, the pantry list and the eat-first shelf say what is on hand; the plan says what the week needs. Iowa State's Shopping Tools page gives the same order: check recipes, cupboards, refrigerator and freezer first, then write the list (Iowa State, Shopping Tools). An item that is already in the house but needed for a meal still goes on the list, ticked, so the list shows the whole week and the tick shows why it was not bought.
EPA's sheet also asks how many meals you will eat at home and how long until the next trip. The plan from The weekly plan answers both.
The list: amounts, meals and store sections
Each line of the list carries four things:
- The item, named the way it is sold ("boneless chicken thighs", not "chicken").
- The amount needed, from the buy formula in How much to buy for the main ingredients and from the recipe for the rest.
- For how many meals. EPA's sheet says to note, next to fresh items, the quantity or the number of meals you are buying for. A bag of greens marked "2 salads" is easier to size in the store than one marked "greens".
- Already have, ticked from the inventory.
Then the order. Iowa State, Utah State's Weekly Menu Planner and Nebraska Extension all group the list by store section, so you walk the store once instead of doubling back (Utah State, Weekly Menu Planner; Nebraska Extension, Use a Grocery List). Nebraska adds that store order works best when you shop mostly at one store, and that stores move items, so the sections are a convention you adjust to your store rather than a fixed sequence.
| Section on the sheet | Typical items | Note |
|---|---|---|
| Produce | Fresh fruit and vegetables, fresh herbs, salad greens | Write the meals each item is for |
| Meat and fish | Raw meat, poultry, fish, deli meats | Pick these up late in the trip; bag them apart from produce |
| Dairy and eggs | Milk, yogurt, cheese, eggs | Late in the trip with the other cold food |
| Bakery | Bread, tortillas, rolls | Half a loaf can be frozen on shopping day |
| Canned and dry goods | Rice, pasta, beans, canned tomatoes, sauces, oil, spices | Check the staples sheet first |
| Frozen | Frozen vegetables, fruit, prepared foods | Last in the cart, first into the freezer |
| Other | Anything that fits nowhere else, and non-food items | Nebraska's catch-all |
Items you buy every week belong on a master list: Nebraska and Iowa State both make them a permanent part of it, checked when needed, and Iowa State posts the list where anyone can add an item as it runs low. The staples sheet from Kitchen inventory is that master list: an item marked "low" or "out" there is added to the shopping list automatically.
Why keep a list? Iowa State's reason is specific: trips to the store for one or two forgotten items lead to impulse buying. The list does not promise a smaller bill; Review and adjust measures what it changed.
2. Unit price and cost per serving
A unit price is the cost per unit of measure of a product, such as the cost per ounce or per milliliter. That is NIST's definition in its 2025 Unit Pricing Guide (NIST SP 1181, Unit Pricing Guide, 2025). It lets you compare two sizes, two brands or two forms of the same food on one scale. The arithmetic is one division:
Unit price = price ÷ quantity, in one unit.
University of Illinois Extension's Shopping to Save sheet works it for a 56 oz package at $5.49: $5.49 ÷ 56 oz = about $0.098 per ounce (Illinois Extension, Shopping to Save).
The division only works when both packages are measured the same way. NIST's guide lists the units a store may use, and they fall into three kinds:
| Kind | US units | Metric units | Examples |
|---|---|---|---|
| Weight | per ounce, per pound | per 100 g, per kilogram | Cheese, meat, rice, cereal, salad greens |
| Liquid volume | per fluid ounce, pint, quart or gallon | per 100 mL, per liter | Milk, juice, oil |
| Count | per piece, per count, each | the same | Eggs, tortillas, single avocados |
Weight, volume and count are not compared with each other. An ounce of weight and a fluid ounce of volume are different units that share a word (How much to buy, measures). The unit price comparer refuses that comparison and asks you to compare items sold the same way.
Three more points from NIST's guide matter in the aisle:
- "Servings", "loads" and "uses" are not units of measure. NIST says so directly, and the 2026 model regulation in NIST Handbook 130 lists only weight, volume, count, area and length units (NIST Handbook 130 (2026), Uniform Unit Pricing Regulation). A shelf tag that gives a price per serving is not a unit price.
- Stores do not all use the same unit. NIST's guide shows shelf labels with a widespread lack of uniformity. When two tags use different units, do the division yourself in one unit. Product-specific
- Shrinkflation is a cut in a package's net contents without a matching cut in price,. NIST's guide says its effect is a higher unit price, so the unit price shows what the package hides.
Unit pricing is voluntary in the United States unless a state requires it. NIST's 2025 guide counts 16 states plus the District of Columbia, Puerto Rico and the Virgin Islands with unit pricing laws or regulations; the guide lists them. Elsewhere a store may show unit prices or not. If your store's tags show none, the package's net quantity and the price are enough for the division.
A bigger package can cost more per unit than a smaller one. Iowa State's unit pricing page compares three bags of carrots: 1 lb of baby carrots at $0.99 ($0.99 a pound), 2 lb of baby carrots at $1.89 ($0.94 a pound) and 1 lb of full-size carrots at $0.68 ($0.68 a pound). The full-size bag is the lowest unit price, and Iowa State adds the condition that settles it: whether you have time to peel and cut them that week (Iowa State, Compare Unit Prices). The unit price is a fact about the package; the better buy depends on your week.
A lower unit price helps only if the food is used before it spoils and there is room to store it. Nebraska Extension's page on meals for one or two puts it plainly: bulk may be half the cost, but it is just as expensive if you toss half. The unit price does not know how much your household eats; your plan and your waste log do.
Cost per serving
Cost per serving is the price divided by the number of servings in the package. Iowa State takes the servings from the Nutrition Facts label and compares two cereal boxes with the same ¾ cup serving size, one with 10 servings at $2.29 and one with 15 servings at $3.99. That is about $0.23 and $0.27 a serving, so the smaller box costs less per serving.
Two cautions. The label's serving size is not your household's portion (serving size and portion): if you eat twice the label serving, each serving costs you twice as much. And compare cost per serving only between packages with the same serving size, as Iowa State's example does. Cost per serving is a planning figure you work out, not a unit price. The comparer gives one when you enter the servings from the label.
For a meal, add the cost of each ingredient as used. A 2-lb pack of chicken thighs used for five meals costs one fifth of its price per meal, before the rest. This manual sets no cost per meal.
3. Store brands, convenience forms and bulk
Three choices come up in most aisles: which brand, which form and which size. Each costs money, time or waste.
Store brands and shelf placement
A store brand (also called a private label) is a product sold under the store's own name. Iowa State's vegetable aisle page says store brands are usually lower priced and often packed by the same manufacturers as name brands (Iowa State, Aisle by Aisle: Vegetables). "Often" leaves room for exceptions, and the label does not say who made it. Iowa State's grains page suggests the test that settles it for your household: a blind taste test of the store brand against the one you usually buy (Iowa State, Aisle by Aisle: Grains). Test it
Where a product sits on the shelf is part of the store's design. Illinois Extension says bargain brands are usually on the lower shelves and name brands at eye level. Missouri Extension's Eating on a Budget poster says to look on the top and bottom shelves and to try store brands (Missouri Extension, Eating on a Budget (N1028)). Cooperative Extension adds that an end-of-aisle display may not be a special (Cooperative Extension, Stretching Your Food Dollar).
Convenience forms: money, time and waste
A convenience form is a food sold partly prepared: washed and bagged greens, baby carrots, precut fruit, frozen chopped vegetables, canned cooked beans, jarred sauce, rice mixes. Iowa State's vegetable page asks three questions of each: how much waste, how much time saved, and whether nutrition differs. It says baby carrots usually cost at least twice as much as regular carrots and pre-washed greens spoil quickly once opened; its own carrot example above shows a smaller gap, so read your store's tags. Product-specific
USDA's Thrifty Food Plan, 2021, says at-home preparation "does not mean all foods are assumed to be prepared 'from scratch'" and includes forms such as frozen precut vegetables, canned precooked beans and jarred pasta sauce in its market baskets (USDA, Thrifty Food Plan, 2021). For a small household a convenience form can be the lower-waste choice: frozen vegetables let you use one serving and keep the rest.
Bulk and multi-buy deals: only when it will be used
Bulk here means a larger package, a bulk bin or a multi-buy deal (two for one, buy one get one) that gives a lower unit price for buying more. Illinois Extension says bulk is typically cheaper per unit, and asks first whether you will use it before it goes bad and whether you have room to store it. Cooperative Extension says large sizes are not a bargain if they go stale or spoil first. EPA says bulk and buy-one-get-one deals save money only if the food is used before it spoils (EPA, Preventing Wasted Food At Home).
The test fits in one line of the list: amount in the bulk package ÷ amount the plan uses per week = weeks to use it, then check that against how long the food keeps on the storage card. To make bulk fit a small household, freeze part on shopping day (Nebraska Extension repackages bulk meat into freezer bags; Nebraska Extension, Planning Healthy Meals for One or Two), or keep dry bulk-bin food in airtight containers labelled with contents and date, as EPA suggests. The freezer's own limits are in Prep and batch cooking. Test it
Seasons and forms. Iowa State says produce in season is usually less expensive, and lists fresh, frozen, canned and dried as forms to compare; Illinois suggests frozen and canned produce in winter. A unit price per ounce compares the forms.
4. In the store and on the way home
Two labels taught earlier are used in the store: the date and, for some households, the allergen statement.
Dates. Under federal guidance, a "Best if Used By" date is about quality, "Sell-By" is for the store's stock, and "Use-By" is the last date for peak quality, not a safety date except on infant formula (FSIS, Food Product Dating). In the store, ask whether the date leaves time to eat the food on the day the plan uses it. Rules vary by place; California's AB 660 makes "USE by" a safety date on food made from July 1, 2026, and How long food keeps has the reading and where to check yours (date labels).
Allergens. If anyone in the household has a food allergy, FDA says to read the label every time you buy a product, because ingredients can change, and that "may contain" statements are voluntary (FDA, Have Food Allergies? Read the Label). The label-check routine is in The people at your table; whether a product is acceptable for a person is settled by that person's allergist, not by this manual. Ask the authority
Damage. FDA's produce page says to buy produce that is not bruised or damaged and to buy pre-cut produce only if it is refrigerated or surrounded by ice (FDA, Selecting and Serving Produce Safely). Damaged cans stay on the shelf (damaged cans).
Getting groceries home within 2 hours
FDA says not to leave groceries in the car longer than necessary, and not more than 2 hours, or 1 hour on a hot day (FDA, Refrigerator Thermometers: Cold Facts about Food Safety). FSIS sets the hot-day line at above 90 °F (32 °C). The 2 hours count from when cold food leaves the store's refrigeration, so pick up refrigerated and frozen food last, bag raw meat apart from produce (FDA's produce page), go straight home, and put cold food away first.
The rule is the same 2-hour rule as in How long food keeps: bacteria grow fastest between 40 °F and 140 °F (4 °C and 60 °C), the danger zone. Cooperative Extension's budget page says the same in shopping terms: go straight home after shopping. For delivery or pickup, the clock runs from when the order leaves the store's cold storage, which you may not know; put cold food away as soon as it arrives.
At the door, move older items forward so the new ones go behind them, and put anything to eat first on the eat-first shelf.
5. A weekly food budget
A food budget here is the amount your household chooses to spend on food in a week. This manual gives a method for setting it and a federal reference to compare it with. It does not say what the figure should be, and it is not financial advice.
Start from your own spending. Penn State Extension's food spending plan begins with a record: every food purchase for a month, every grocery trip and every cup of coffee, "to the penny"; then a review, then a monthly amount, tracked on the list, in an app or with weekly cash envelopes (Penn State Extension, How to Make a Food Spending Plan). Your starting week recorded one baseline week the same way. With two or more weeks on the spending sheet, the household has its own numbers to set a budget from: the average of the weeks, or the baseline with one change, or any figure the household decides.
Keep groceries and food eaten out in separate columns, as the spending sheet does; the USDA reference below covers only food made at home.
Write the figure on the budget sheet with how it was set ("from our own spending", "from a USDA reference figure", or both) and the date. Review and adjust compares the planned week's spending with it.
The USDA Food Plans as a reference
The USDA Food Plans are four estimates of what a nutritious diet made at home costs each month: Thrifty, Low-Cost, Moderate-Cost and Liberal. USDA publishes the costs every month for 15 age and sex groups, from a child of 1 year to adults 71 and over (USDA, Monthly Cost of Food Reports). The Thrifty Food Plan is the lowest-cost of the four; USDA's Food Plans page says the Low-Cost, Moderate-Cost and Liberal plans represent the second-lowest, second-highest and top quartiles of food spending (USDA, USDA Food Plans).
The arithmetic, from the reports' footnotes:
- Look up each person's weekly cost in the plan level you want to compare with, by age and sex.
- Add them up.
- Apply the household-size adjustment. The costs are for people in four-person households. USDA suggests adding 20 percent for one person, 10 percent for two and 5 percent for three; no change for four; subtracting 5 percent for five or six people and 10 percent for seven or more.
- For a monthly figure, multiply the weekly one by 4.333.
The budget reference page does this for up to eight people. Its figures are from the August 2026 report, issued in September 2026, the latest USDA had posted when we checked on October 16, 2026; this manual refreshes them at its yearly link check. USDA rounds each printed figure to the nearest 10 cents, so a sum the calculator makes can differ from a table by 10 to 20 cents.
What the plans assume matters more than the arithmetic:
- Every meal and snack is made at home. Both the Thrifty report and the three-level report say so in their footnotes. A household that eats out or orders in some nights, or gets school meals, buys fewer groceries than the reference assumes.
- Some planning and some convenience. The Thrifty Food Plan, 2021, says the plan requires some planning and preparation and includes convenience forms. It also adds a 5 percent allowance for food that spoils or is left on the plate, while noting that consumer-level waste estimates run about 20 percent or higher.
- Not a shopping list or a diet. The same report says the plan is not an item-specific shopping list or a prescriptive diet.
- A U.S. average. USDA publishes separate Thrifty figures for Alaska and Hawaii; outside the US the plans do not apply.
The USDA Food Plans are a reference for comparison, not a recommended budget, and this manual gives no financial advice. A figure above or below a reference is not a verdict on a household; what to spend is the household's decision. Grocery receipts also leave out food from other sources, such as school meals, WIC foods or a pantry. This manual does not promise that a list or a budget lowers spending; Review and adjust compares the household's own weeks.
The Grant household is one of this manual's fictional cases; its amounts and prices are invented for the examples. Teresa (38) and Malik (40) Grant have two children, Ava (9) and Leo (4). Their two-week baseline was $412 in groceries plus $96 eaten out: about $206 and $48 a week.
On the budget reference page they enter Malik as male 19 or 20 to 50, Teresa as female 19 or 20 to 50, Ava as child 9 to 11 and Leo as child 4 to 5. With four people the household-size factor is 1.00. The August 2026 weekly references:
| Person (group) | Thrifty | Low-Cost | Moderate-Cost | Liberal |
|---|---|---|---|---|
| Malik (male 19 or 20 to 50) | $73.60 | $73.20 | $91.90 | $112.20 |
| Teresa (female 19 or 20 to 50) | $58.50 | $63.60 | $77.60 | $99.00 |
| Ava (child 9 to 11) | $55.80 | $62.50 | $80.70 | $94.00 |
| Leo (child 4 to 5) | $43.50 | $41.30 | $51.10 | $61.80 |
| Household of four, × 1.00 | $231.40 | $240.60 | $301.30 | $367.00 |
Known: their own groceries, about $206 a week, from receipts. Assumed by the reference: every meal and snack made at home, which is not their week (about $48 a week eaten out), and no food from elsewhere, while Leo's WIC benefits cover some of his milk, cereal and produce, which are not on their receipts. Open, and who settles it: which reference, if any, they compare with, and what weekly figure they write on the budget sheet. Teresa and Malik settle both; neither the calculator nor this manual gives a verdict. Which WIC items to use first in each benefit period is settled by their WIC office's rules.
Shared staples in a shared house
When housemates share some food, the shared part of the budget is a division, and the rule for dividing is theirs: an equal split, a split by use, or taking turns buying. None is more correct.
The house on Alder Street (fictional; amounts invented): Kai Brennan, Noor Haddad and Ben Osei share rice, oil, spices, coffee, milk and eggs. In their baseline week the shared staples cost $36. Split equally, that is $36 ÷ 3 = $12 each. Open, and who settles it: whether an equal split fits their use (Noor is vegetarian and the three eat their main meals at different times); the housemates settle it. This manual gives the arithmetic, not the rule.
How the USDA plans are built
Each plan has two parts, USDA's Food Plans page says: market baskets (weekly quantities of foods in purchasable form) and the cost of buying them. The four plans were not built together.
- Thrifty: reevaluated in 2021, on 2013-16 consumption and 2015-16 price data, updated monthly with the Consumer Price Index. Its June cost for the reference family of four sets the maximum SNAP allotments for the next fiscal year. USDA's page says the next reevaluation is required to be no earlier than October 1, 2027.
- Low-Cost, Moderate-Cost and Liberal: cost levels last set in 1983 and market baskets last reevaluated in 2007, on 2001-02 data, also updated with the Consumer Price Index. Their tables use 2007-era age bands (14 to 18 and 19 to 50) where Thrifty says 14 to 19 and 20 to 50.
Because the baskets come from different decades, the four levels are not a smooth ladder. In the August 2026 tables a child of 4 to 5 costs $43.50 a week in the Thrifty plan and $41.30 in the Low-Cost plan: the "lowest" plan is higher for that age. USDA's monthly page also warns that costs from different market baskets should not be joined into one continuous series, so a figure from 2019 and one from 2026 are not directly comparable.
Iowa State's meals-away method
Iowa State's Spend Smart grocery budget calculator starts from USDA's Low-Cost plan and adjusts each person for meals eaten away from home: from each person's weekly amount it subtracts 1/21 for each meal eaten away, since a week has 21 meals, and then applies USDA's household-size percentages (Iowa State, What You Spend). For a child whose weekly reference is $55.80 and who eats five school lunches a week, the arithmetic is $55.80 × 16/21 = about $42.51. This is Iowa State's method, not USDA's; the budget page offers it as an optional, labelled line.
6. Food help, for anyone
These references are here for every reader. This manual asks nothing about income and does not judge who uses them; they can also help a neighbor or a relative.
| Reference | What it is | How to reach it |
|---|---|---|
| WIC (USDA) | The Special Supplemental Nutrition Program for Women, Infants, and Children. USDA's page says it serves women who are pregnant, recently pregnant or breastfeeding, and children under 5; anyone raising a child under 5 can apply for the child. | The state and tribe locator on USDA's WIC page |
| USDA National Hunger Hotline | A hotline that finds meal sites, food banks, government programs and other services near you. USDA's page says Hunger Free America operates it. | Call 1-866-3-HUNGRY (1-866-348-6479), Monday to Friday, 8 a.m. to 8 p.m. Eastern; or text 914-342-7744 with a keyword such as "food" |
| Feeding America food bank locator | A search of the food banks in Feeding America's network. A food bank stores donated food; a food pantry is where people pick food up. Feeding America says anyone who needs extra help affording food can visit a pantry, and some pantries have requirements such as living in an area. | Enter a ZIP code on the locator page |
| SNAP-Ed Connection (USDA; not linked, because its address no longer loads, checked 2026-10-27) | A library of recipes, menus and a seasonal produce guide. Federal SNAP-Ed funding ended on October 1, 2025, with unspent funds usable through fiscal year 2026, according to the National Conference of State Legislatures (NCSL, 5 Changes the Beautiful Bill Is Bringing to SNAP). We cite the site as a library, not a program to join. | The site's Resources menu |
Benefit and pantry food often comes with its own timing. Michigan State University Extension lists food benefits that must be used before they expire, and food from charitable organizations, among the questions to ask when choosing meals (Michigan State University Extension, How to master meal planning). Those items go on the eat-first list in The weekly plan before anything is bought. Which benefit items must be used first is set by the program's rules; ask the office that issues them. Ask the authority
7. Coupons, trip frequency and prices Go deeper
Coupons: where the sources differ
Extension sources disagree on coupons, and none gives data on what they save a household.
- Illinois Extension says many stores let you use an electronic manufacturer coupon and a store coupon together "for double the savings".
- Missouri Extension says to use coupons only for items you would normally buy.
- Cooperative Extension says most coupons are for more expensive, highly processed foods, gives an unsourced "about 10%" saving for a few categories, and warns against a coupon for a food that still costs more than the store brand.
The arithmetic that reconciles them is the unit price after the coupon, (price − coupon) ÷ quantity, compared with the store brand's. NIST's 2025 guide says unit prices belong on digital coupon offers too. This manual recommends no coupon strategy.
How often to shop
Illinois Extension says to plan menus for one or two weeks and shop once. Missouri Extension says to shop only once a week. Iowa State says extra trips for forgotten items lead to impulse buying. Against fewer trips sits the storage card: greens bought on day one of a two-week shop may not last into the second week. The trade-off is yours to settle. The fictional Grant household uses a main trip and a midweek top-up for milk and produce; your waste log shows whether the second week's produce is the problem.
Food prices change
USDA's Economic Research Service forecasts food-at-home (grocery) prices to rise 2.4 percent in 2026, with an interval of 1.8 to 3.0 percent, in its September 2026 forecast (USDA ERS, Food Price Outlook: Summary Findings). That is why the budget page's figures drift between yearly refreshes. It is a national forecast, not a prediction for your store.
Unit price rules where a state has them
NIST Handbook 130's Uniform Unit Pricing Regulation is a model rule: it is binding only where a state adopts it, and it applies only when a store gives unit prices. Under it, unit prices of $1 or more are rounded to the nearest cent, and packages under 1 oz (28 g) or 1 fl oz (29 mL), or priced at 50 cents or less, are exempt. Your state's weights and measures office is the authority on what its stores show. Ask the authority
8. See it: Jordan's list See it
Jordan Pike (29, lives alone, they/them) is this manual's smallest-setup case; the amounts, prices and results here are invented for the examples. Jordan shops on Saturday at one supermarket. The plan from The weekly plan is chicken thighs with rice and salad on Sunday, a salad with eggs on Monday, chicken tacos on Tuesday, pasta with sauce and frozen vegetables on Wednesday, out on Thursday, ordered in on Friday, an eat-down night on Saturday, and black bean quesadillas from staples as the backup.
| Section | Item | Amount needed | For how many meals | Already have |
|---|---|---|---|---|
| Produce | Salad greens | One package | 2 salads (Sun, Mon) | |
| Produce | Cilantro | 1 bunch | 1 (Tue tacos) | |
| Meat and fish | Boneless chicken thighs | 2 lb | 5 (3 dinners, 2 lunches) | |
| Dairy and eggs | Eggs | 4 for Monday's salad | 1 | ✓ |
| Bakery | Tortillas | 1 pack | 2 (Tue tacos, backup) | |
| Canned and dry goods | Rice | For 2 meals | 2 (Sun, Wed lunch) | ✓ |
| Canned and dry goods | Canned black beans | 1 can | 1 (backup) | ✓ |
| Canned and dry goods | Jarred pasta sauce | 1 jar | 1 (Wed) |
The unit price. Greens come in a 5 oz clamshell at $3.99 and a 10 oz bag at $5.49. Jordan does the division: $3.99 ÷ 5 oz = about $0.80 an ounce; $5.49 ÷ 10 oz = about $0.55 an ounce. The bag is cheaper per ounce. It is also the size Jordan threw out most of in the baseline week, marked "spoiled". The list says two salads. Jordan buys the clamshell and writes both unit prices in the list's unit price column.
Known: the list, the ticks for rice, eggs and black beans from the inventory, and the two unit prices. Assumed: that 5 oz covers two salads; that is Jordan's assumption from the baseline week, not a measurement. Open, and who settles it: whether the clamshell was the right size and whether the bigger bag would have been used this time. Jordan's waste log for the week settles it. Jordan writes the Saturday receipt total on the spending sheet in the row under the baseline week's $94.
Free sources behind this chapter:
- EPA, Smart Shopping: Shop with Meals in Mind: the one-page list template with amount-needed and already-have columns that this chapter's list follows.
- NIST, Unit Pricing Guide (SP 1181, 2025): the definition, the permitted units, shrinkflation and the list of states with unit pricing laws, with examples of shelf labels.
- Iowa State, Compare Unit Prices for the Best Buy: worked carrot and cereal examples of unit price and cost per serving.
9. Practice: one list, one trip, one receipt Practice
Minimum: one list made from the plan and used for one trip, two unit prices compared, and the receipt total on the spending sheet. Time: about 30 minutes before the trip, plus the trip. Materials: the weekly plan, the inventory lists from Kitchen inventory, the purchase amounts from How much to buy, a phone calculator or this manual's unit price comparer, and the receipt.
- Open the plan and the inventory side by side. For each planned meal, list what it needs, and tick anything already in the fridge, freezer or cupboard on the shopping list sheet.
- Add the amounts. Copy the purchase amounts from How much to buy for the main ingredients, and write the number of meals beside each fresh item.
- Add staples that are low or out from the staples sheet.
- Set each line's store section and sort the list by section.
- Pick two items you buy often that come in two sizes or two brands. Enter both in the unit price comparer, or divide price by quantity in one unit yourself. Write the lower unit price in the list's unit price column.
- Shop from the list, with refrigerated and frozen food last, and go straight home. Put cold food away first.
- Tick "bought" on each line, and write the receipt total in a new row on the spending sheet, below the baseline week. Food bought off the list goes in the notes column, with what it was.
- Set a weekly budget. When the spending sheet has two or more weeks, choose a weekly figure from them and write it on the budget sheet with "from our own spending".
- Look at the USDA reference. On the budget reference page, enter each person's age and sex group and your weekly grocery figure. Note which plan level you looked at, if any, on the budget sheet. The page shows the figures side by side and states no verdict.
10. Your kitchen Your kitchen
11. Check your work Check your work
Criteria
- Does every planned meal's main ingredient appear on the list, either to buy or ticked as already had?
- Does each fresh item say how many meals it is for?
- Is the list ordered by store section, in an order that fits your store?
- Were two unit prices worked out in one unit each, comparing weight with weight, volume with volume, or count with count?
- Did cold food reach the refrigerator or freezer within 2 hours of leaving the store's refrigeration?
- Is the receipt total on the spending sheet in its own row, with food eaten out kept in its own column?
Worked example
Jordan's list (fictional) meets each criterion. The five uses of chicken, both salads, the tacos and Wednesday's pasta all have their ingredients on the list, with rice, eggs and black beans ticked. Each fresh item has its meals beside it. The list runs produce, meat, dairy, bakery, dry goods, the order of Jordan's supermarket. The two unit prices are both per ounce of weight. Jordan picked up the chicken last and drove straight home. The receipt total is in a new row under the baseline. What the list does not show yet is whether the clamshell covered both salads, or whether the week's spending differs from the baseline; the week and Review and adjust settle those.
Common mistakes
- Writing the list from memory instead of from the plan and the inventory, so items already in the house get bought again.
- Comparing a price per fluid ounce with a price per ounce of weight. Check the unit on both tags.
- Choosing the lowest unit price for a perishable without asking how much the plan uses. The bigger package is cheaper per unit only if it is eaten.
- Treating a shelf tag's price per serving as a unit price. Servings are not a unit of measure, and the label's serving may not be your portion.
- Running errands with groceries in the car. The 2 hours start at the store.
- Setting a budget from a USDA reference before the household has any weeks of its own spending.
What is still unresolved
This chapter cannot say whether shopping from a list changes what your household spends or wastes. One planned week, measured the same way as the baseline, shows that for your household, and Review and adjust makes the comparison. What weekly figure to set as a budget, and which USDA reference to compare with, if any, are the household's decisions. Which store brands your household accepts is settled by trying them.