Buy One Get One vs. Percent Off: Which Deal Is Actually Better?

When you buy the full quantity the deal asks for, every multi-buy offer equals a simple percentage off each item:

So a BOGO 50% off deal is weaker than a plain 30% off — but a BOGO free deal beats 30% off, if you need two.

A jar of pasta sauce is $3.79. Store A has buy one get one free. Store B has 30% off.

1. Store A (BOGO free): $3.79 for 2 jars → $1.90 per jar.
2. Store B (30% off): $3.79 × 0.70 ≈ $2.65 per jar.
3. If you need two jars, BOGO is about 29% cheaper per jar.
4. If you need only one, BOGO costs $3.79 for the jar you use — Store B is cheaper at $2.65.

The second jar is only “free” if you would have bought it anyway, or if it keeps until you need it.

Store A has 12 oz bags of coffee at $8.99 with buy one get one 50% off. Store B has a 30 oz canister for $15.99 with no deal.

1. Store A: 2 bags = $8.99 + $4.50 ≈ $13.49 for 24 oz → about $0.56 per oz.
2. Store B: $15.99 ÷ 30 oz ≈ $0.53 per oz.
3. The canister without any deal is about 5% cheaper per ounce.

A deal sign makes Store A look like the bargain, but per ounce it isn’t. Enter both in the calculator below — use the multipack field for “2 × 12 oz” and the total you would pay.

• BOGO free: enter the price of one item as the price, the size of one item, and 2 in the × field.
• BOGO 50% off: price = 1.5 × the single price, × 2 items.
• 3 for 2: price = 2 × the single price, × 3 items.
• Percent off: price = single price × (1 − discount), e.g. × 0.7 for 30% off.

Rules vary by store. At some stores, “2 for $5” simply means $2.50 each and you can buy one; at others you need both to get the price. BOGO deals usually need both items. Check the shelf sign or ask — and if you only need one item, compare the price you would pay for one.

1. Convert the deal into a price per item (or per ounce) for the quantity you will buy.
2. Compare with other sizes and brands at their normal price — not just with the crossed-out price.
3. Only count free or discounted items you will actually use before they expire.
4. Stack a coupon only if the store allows it, and subtract it before comparing (see coupons and cashback).
5. Check your price book: is the deal price below what you usually pay?

For packs of items, the cost per item calculator is ready to use; for coffee, the coffee price per pound calculator.

The unit price printed on a shelf tag is usually based on the regular price of one item. A BOGO or multi-buy offer on a separate sign may not be reflected in it. Work out the deal’s own price per unit — the table at the top of this guide gives the percentage — and compare that with the other sizes. If the deal is a percentage, the unit price drops by the same percentage: 25% off a $0.40/oz product makes it $0.30/oz.

Some deals have limits, such as “limit 4” or “with store card”. Only count the deal price for the quantity you can actually buy at it; anything beyond the limit is at the regular price, so work out the average price per unit for the whole quantity you plan to buy.