297 products. 40 chains. One chart that shows why "the cheapest store" is a myth — the answer changes for every product you buy.
Each column below is one product (identified by UPC barcode). Each dot shows what percentage more a chain charges above the cheapest available price — so the bottom of every column is 0% (the best deal). The amber band shows the total spread. Large dots highlight four major chains: Safeway, Target, Walmart, and Whole Foods. Hover any dot to see all chains and exact prices.
The median price spread across these 297 products is 42%. That means for a typical item in your cart, the most expensive store charges 42% more than the cheapest — on the exact same product, same brand, same size, same barcode.
On a $150 weekly grocery run, even modest optimization — switching stores on just the 5 most overpriced items — could save $15–25 per trip, or $800–1,300 per year.
Why this chart matters: Most "price comparison" advice says "shop at Walmart" or "get a Costco membership." This data shows the answer is product-specific. The cheapest store for your cereal is not the cheapest store for your olive oil. No single chain wins across the board.
Products with spreads above 100% are overwhelmingly specialty items — artisan condiments, premium ice cream, imported preserves. These are exactly the items where lazy store loyalty costs the most.
Even basic grocery items — peanut butter, orange juice, bagels — show spreads of 38–142%. These aren't niche products. These are in every cart, every week.
Most products cluster in the 25–75% spread range. Only 13 of 297 products (4%) show a spread under 10% — meaning near-universal pricing is extremely rare. Nearly 1 in 5 products shows a spread above 75%.
The long right tail — products where the most expensive chain charges 2–5× the cheapest — isn't a data artifact. These are real barcodes at real stores, verified by receipt photos in the Open Food Facts Prices database.
The chart above makes a visual argument that no table or summary statistic can: price variation is the rule, not the exception. Nearly every product has a meaningfully different price depending on where you buy it. The spread isn't random — it's structural, driven by chain markup strategy, supplier deals, and local competition.
A family spending $600/month on groceries could realistically save $60–120/month by checking prices per item rather than per store. Over a year, that's $720–1,440 — a month's rent in many California cities.
No human can track 297 products across 40 stores. But a receipt scanner can. That's why we built AfterCart.
This is especially valuable for SNAP recipients and budget-constrained families.
When you can't afford to guess wrong, having real price data — not brand reputation, not conventional wisdom — is the difference between making rent and not.