Which is the better deal: “buy one, get one free” (BOGO), “buy two, get one free,” or “second item 50% off”? The honest answer is that it depends on one number you already know — how many items you actually want. The two offers sound like siblings, but they discount at very different rates. This guide puts a unit price on each one so the choice becomes arithmetic rather than gut feel.
Why Unit Price Is the Right Measure
Headline percentages lie because they hide the quantity. Saying “50% off” and “buy one get one free” both feel like the same half-price win, but one is tied to pairs and the other to the count you carry to the register. The unit price — what one item costs inside the deal — removes the guesswork. You compare offers on the same basis: the money you hand over divided by the items you walk away with.
The Three Offers, Side by Side
Work a real order of six items at $10 each and watch the unit price separate the promotions clearly:
| Offer | You pay (6 items) | Price per item | Your discount |
|---|---|---|---|
| Buy 1, get 1 free (BOGO) | $30 | $5.00 | 50% |
| Buy 2, get 1 free | $40 | $6.67 | 33% |
| Second item 50% off | $45 | $7.50 | 25% |
BOGO halves the per-item cost to $5 each — a clean 50% discount. Buy-two-get-one-free shrinks the cost to roughly $6.67 — a third off. Second-item-half-off only pares it to $7.50, a quarter off. At the same quantity and price, they are not close: BOGO beats second-half-off by exactly double the saving.
Why Second-Item-Half-Off Lags So Far
A “second item 50% off” deal is not half off everything; it is half off every other item. Pair the six units: items one and two become $10 and $5, items three and four repeat, and items five and six repeat. Three pairs each contribute one full price and one half price, so the average creeps up to $7.50 rather than $5. It still saves money — 25% is real — but the sign overstates how deep the cut is, because only half your items take the discount.
When Each Promotion Makes Sense
BOGO is the best unit price and the right pick whenever you genuinely want an even number of items and can use both. If you need four jars of jam, BOGO turns that into two full-price jars with two free — the sharpest outcome. Buy-two-get-one-free earns its keep when you need exact trios people consume together, like three bottles of sauce or three T-shirts; its 33% still beats the 25% of the pair deal. Second-item-half-off is the weakest of the three at equal quantities, and it tends to shine only when the store puts the discount on the pricier item in a pair, letting you skew the maths in your favour.
There is one more layer every comparison must add: the quantity. BOGO only hits 50% on even counts. Buy three items under BOGO and the odd one drags the unit price up, shrinking the gap. What matters is not which offer sounds best on a billboard, but which one best fits the number of items you are prepared to buy and genuinely use.
Set your price, your quantity, and your promotion type in the DiscountVibe discount calculator to compare BOGO, buy-two-get-one, and second-half-off by unit price before you choose.