How to Compare Grocery Prices Across Different Stores
If you already shop at more than one store, you’ve probably noticed the same items cost wildly different amounts depending on where you buy them — but keeping track of which store is cheapest for what is impossible to do in your head. That’s exactly what a grocery price book solves: a simple spreadsheet that compares prices across stores per item, so you always buy each staple where it’s actually cheapest. Here’s how to build and use one.
Why “which store is cheapest?” is the wrong question
People pick a store the way they pick a team — “Aldi is cheap,” “Whole Foods is expensive” — and shop there loyally. But no store is cheapest on everything. The discount store that crushes on produce might be pricey on your specific brand of coffee. The warehouse club that wins on bulk paper goods loses on small quantities of fresh food.
The right question isn’t which store is cheapest — it’s which store is cheapest for this item. Answer that across your 20-30 most-bought staples and you can split your list so every item is bought at its best price. That’s where the real savings live, and it’s invisible until you write the prices down side by side.
Build the price book: items down, stores across
Set up a grid. List your staple items down the left, your stores across the top, and fill in the price you pay for each:
| Item | Aldi | Walmart | Kroger | Costco | Cheapest |
|---|---|---|---|---|---|
| Milk (1 gal) | 3.29 | 3.15 | 3.49 | 3.05 | Costco |
| Eggs (dozen) | 2.79 | 2.99 | 2.89 | 2.60 | Costco |
| Chicken breast (lb) | 3.49 | 3.29 | 3.19 | 2.99 | Costco |
| Bread (loaf) | 1.29 | 1.48 | 1.79 | 2.20 | Aldi |
| Coffee (12oz) | 4.49 | 4.99 | 5.29 | 3.80 | Costco |
The “Cheapest” column is one formula — =INDEX(store_headers, MATCH(MIN(price_row), price_row, 0)) — which returns the name of the lowest-price store for that row automatically. Fill it down and your whole list tells you where to buy each item at a glance.
Compare the whole basket, not just single items
Single-item comparison is useful, but the decision you actually make is where to do the main shop. So total each store’s column for your standard basket:
Worked example. A shopper prices their 25 staples at four stores and sums each column: - Aldi basket total: $118.40 - Walmart: $121.10 - Kroger: $126.75 - Costco: $112.90 (on the items it sells)
Costco wins the basket — but Aldi is cheapest on bread, produce and a few pantry items. The efficient move isn’t “drive to all four.” It’s a main shop at Costco plus a quick Aldi stop for the handful of items with the biggest gaps. The spreadsheet shows the second stop saves about $9 on those items — worth it on the way home, not worth a special trip.
That’s the judgement a price book lets you make: is the extra stop worth $9, or only $2? You can finally answer with a number instead of a hunch.
Keep it current without obsessing
Prices drift, so refresh your staple prices every couple of months and update any item the moment you notice a big change. You don’t need a live feed of every price in the store — just a reliable reference for the 20-30 items that make up the bulk of your spending. That’s the 80/20 of grocery pricing.
Watch for the tricks that hide the real price
A price book only works if you’re comparing the real per-unit price, and stores are surprisingly good at obscuring it. Three traps to write into your notes:
- Different package sizes. Store A’s “cheaper” cereal box is 12oz; Store B’s is 18oz. The shelf prices look comparable, but the per-ounce cost isn’t. Always record the size next to the price, and compare cost per ounce, not per package. (This is the same unit-price logic behind deciding whether buying in bulk is actually cheaper.)
- Sale prices masquerading as regular. A price marked “$2.49 (was $3.99)” isn’t your baseline — it’s temporary. Note whether a price is a sale or the everyday price, or your price book will tell you a store is cheap when it’s just having a good week.
- Loyalty-card pricing. Some stores show two prices: card and non-card. Record the one you’ll actually pay. If you don’t have the card, the shelf’s lower number is fiction.
Once your price book distinguishes real everyday prices from sale prices and matches sizes properly, it becomes genuinely trustworthy — and you can shop from it with confidence instead of re-checking every aisle.
A price book pays off most on your top 20 items
You don’t need to price every product in the store. Grocery spending follows the 80/20 rule hard: a small set of staples — milk, eggs, bread, chicken, coffee, the specific things your household buys every week — makes up the bulk of your bill. Price those 20-30 items well and you’ve captured almost all the available savings. Everything else is noise. Building a price book of your actual top items, rather than an exhaustive catalogue, is the difference between a tool you keep using and a project you abandon.
Skip the setup with a built price comparison
Wiring up the INDEX/MATCH “cheapest store” formula and basket totals across four stores is fiddly to build and easy to break. Our Grocery Budget & Coupon Savings Tracker includes a ready-made Store Price Comparison tab that compares 30 staple items across 4 stores and flags the cheapest option for every item automatically — no formula-building required. It sits in the same file as your Expense Log and Dashboard, so the store where you actually shop and the store that’s cheapest are tracked together, and you can act on the gap immediately.
For the complete grocery-budgeting system this belongs to, see the main guide: how to make a grocery budget spreadsheet that actually works.
Featured on ReadySheetGo: Grocery Budget & Coupon Savings Tracker — built-in Store Price Comparison across 30 items and 4 stores, automatically flagging the cheapest option for each. 11 tabs, 957 formulas, Excel and Google Sheets. $12.99.
Frequently Asked Questions
What is a grocery price book and how do I make one?
A price book is a running list of the items you buy regularly with the price for each at every store you shop. You make one by listing 20-30 staple items down the side, your stores across the top, and filling in the price per item at each store as you notice them. A formula then highlights the cheapest store for each item, so you know exactly where to buy what without memorising hundreds of prices.
How do I know which store is cheapest for groceries?
Don't judge stores by overall reputation — judge them item by item. The same store can be cheapest on produce and most expensive on meat. Track the price of your actual staples at each store in a price book, then compare per item. Most households find no single store wins everything; the savings come from splitting your list so each item is bought where it's cheapest.
Is it worth driving to multiple stores to save on groceries?
Compare the savings against the fuel and time. A price book shows your total basket cost at each store, so you can see whether a second stop saves $15 or $3. A common efficient pattern is a main shop at your cheapest all-round store plus one targeted stop for a few items with big price gaps, rather than driving to four stores every week.
How often should I update my grocery price book?
Prices drift, so refresh your staple prices every couple of months, and update an item immediately whenever you notice a big change or a new regular price. You don't need to re-check everything constantly — the point is a reliable reference for the 20-30 items that make up most of your spending, not a live feed of every price in the store.