Haul MathCompare prices you paid
Did I pay less for this Costco item last time?
Compare the same item and package size, subtract any item-specific discount, and divide by the quantity you received. Use the same basis both times—such as before tax—to find out whether the item actually cost less. A lower package price alone is not enough.
Start with the item number and original receipt. Similar product names can describe a different size or variant. A receipt tells you what you paid on that trip; it does not establish today’s price at another warehouse or online.
A worked example: the same detergent, two trips
Fictional prices and product details · not a current offer
Assume both receipts are for one identical 146-load detergent package and both discounts apply to that item. Exclude tax for this comparison.
| Receipt | Before discount | Discount | You paid |
|---|---|---|---|
| Earlier trip | $19.99 | $4.00 | $15.99 |
| Later trip | $18.99 | $0.00 | $18.99 |
The later ticket price is $1 lower, but you paid $3 more after discounts. Your earlier cost was about 10.95¢ per stated load ($15.99 ÷ 146); the later cost was about 13.01¢ ($18.99 ÷ 146). The later purchase cost about 18.8% more than the earlier one.
Use the item’s net price after discount. If your receipt or app already shows that net amount, do not subtract the coupon a second time. “Loads” is a package claim; actual detergent use can vary.
What if the package size changed?
Suppose an older rice bag cost $24.99 for 25 lb and a newer one costs $21.99 for 20 lb. The new bag costs $3 less at checkout, but the unit prices are about $1.00/lb and $1.10/lb. You receive less rice and pay about 10.0% more per pound.
This is a manual comparison method. Haul Math’s receipt-backed history helps you review recorded purchases; do not assume the app can normalize every package size or infer missing quantities. Confirm size and variant from the original receipt or product packaging.
A lower unit price does not always mean a better buy
Imagine a 5 lb produce pack for $12.00 and a 2 lb pack for $5.50. The large pack is cheaper per pound: $2.40 versus $2.75. But if your household uses only 3 lb before the rest spoils, the large pack costs $4.00 per pound actually used.
Check storage space, how quickly you use the item, and how much you already have. A historical low price is useful context, but it is not a reason to buy more than you need.
Use your receipts to prepare the next shopping list
- Find the last matching item number and check its package size.
- Write down the date, quantity, net item price, and whether the purchase was in a warehouse or online.
- Compare a new offer on the same basis. Check dates, location, channel, and purchase limits at Costco.
- Decide how much you will use before you run out of storage or the product expires.
Haul Math on Android and iPhone keeps your imported receipt archive and basic totals available free. Optional Plus adds receipt-backed item and price history, the full current offer catalog, and exact purchase matches. These help you review your own evidence; Haul Math does not guarantee a future sale or savings.
Prices in this guide are invented to explain the method. The arithmetic is independent of Haul Math, and none of these examples is a live Costco deal.