"Store A is cheaper than Store B" is rarely a fair statement unless it's qualified by which basket of goods was compared, at what package sizes, and at what quality or brand tier. Two stores can each be genuinely cheaper than the other on different categories, and a total-receipt comparison mostly reflects what you happened to buy that week, not a stable pricing advantage.
Build a fixed basket before comparing
The only fair store-to-store comparison uses a fixed basket: the same specific products (or, when exact brand matches aren't available, the closest equivalent at the same quality tier), the same package sizes normalized to unit price, purchased at both stores in the same week. Comparing a name-brand item at one store to a store-brand item at another isn't a fair price comparison — it's a quality-tier comparison wearing a price comparison's clothes. Note also that eggs, milk, and poultry are priced under Canada's supply-management system, so their price spread between stores tends to be narrower than for goods without a managed supply.
Worked example
Example only: a ten-item fixed basket (milk, eggs, bread, chicken breasts, rice, bananas, pasta, canned tomatoes, coffee, paper towels), priced at the same sizes and brands where possible, totals $42.10 at Store A and $45.80 at Store B, before sales tax. That's a real, basket-based 8.1% difference — a far more trustworthy number than either store's own advertising claims about being "the low-price leader."
Fixed-basket comparison (example)
| Store | Basket total | vs. cheaper store |
|---|---|---|
| Store A | $42.10 | baseline |
| Store B | $45.80 | +8.8% |
Decision rule
Decision rule: never conclude a store is cheaper overall from fewer than 8–10 comparable items across varied categories (produce, protein, pantry, household). Category-specific price leadership is common; overall leadership on a narrow basket is often noise.
Store brands complicate honest comparisons
Store or private-label brands frequently offer the best unit price in a category, but they aren't present at every retailer, and their formulation or quality can vary meaningfully between stores even when the packaging looks similar. If your fixed basket includes store brands, note that you're partly comparing each store's private-label program, not just its pricing on identical national brands — both are useful information, but they answer different questions.
Frequency of price checks
Retail prices move item by item throughout the year, so a single comparison trip is a snapshot, not a verdict. If a store comparison genuinely matters to your budget (e.g., deciding where to do most of your shopping), repeat the fixed-basket comparison two or three times over a couple of months before treating the result as reliable — a single week's sale cycle at either store can swing the total by several percent in either direction.
- Compare a fixed, identical (or equivalent-tier) basket, not total receipts from different purchases.
- Normalize every item to unit price before summing the basket, since package sizes differ between stores.
- Use at least 8-10 varied items, not just a couple of categories.
- Repeat the comparison over multiple weeks before treating one store as reliably cheaper.
All figures in this guide are illustrative examples, not current prices. Cotco does not sell products and is not affiliated with any retailer. Verify prices, sizes, and product details with the seller before buying.