The "buy one get one" vs "50% off" test

Quick answer

Mathematically, buy-one-get-one-free and 50 percent off are identical — the buyer pays the same per-unit price either way. Psychologically, they perform very differently. BOGO consistently outperforms 50 percent off in Facebook ads for products under £50, while 50 percent off tends to win for products over £100 and for items with low repurchase frequency. Knowing why lets you pick the right framing instead of guessing.

The psychology

BOGO wins because of two cognitive shortcuts. The first is gain framing: 'get one free' feels like an addition, while '50 percent off' feels like a subtraction. Humans weigh additions to inventory more positively than discounts. The second is anchoring on quantity: when the buyer thinks 'two for the price of one,' the brain anchors on quantity (two), not the discount (50 percent). Quantity feels concrete; percentages feel abstract.

50 percent off wins for higher-priced items because the discount is a bigger absolute pound figure. £100 off a £200 jacket feels enormous. 'Get a second jacket free' makes the buyer wonder 'why would I want two jackets?' For consumables, BOGO wins because doubling consumption is plausible. For durables, the doubling feels wasteful.

Example offer copy

Variant A — BOGO (winner for £29 supplement): Headline: Buy One Bottle, Get One Free — Today Only Primary text: Stock up on our most-loved magnesium supplement. Order one bottle, we send two. No code needed, discount auto-applies at checkout. Limit 4 bottles per customer.

Variant B — 50% off (winner for £180 jacket):
Headline: 50% Off The All-Weather Parka — £180 → £90
Primary text: One day only. The jacket reviewers called 'the only coat I packed for Iceland' is half off until midnight Sunday. Sizes XS to XXL still in stock.

Why it works

The supplement ad wins with BOGO because magnesium gets used daily — a buyer running through one bottle a month genuinely benefits from a second. The framing also turns a maintenance purchase into an inventory event: 'I'm stocking up.' The jacket ad wins with the percentage because £90 is a real, specific amount the buyer can imagine spending elsewhere. BOGO on a £180 jacket would force the question 'do I need two parkas,' which usually answers itself with 'no.' The lesson: match framing to use case, not to category.

FAQs

Does BOGO work for SaaS?

Sometimes — 'buy one year, get one free' on annual plans converts well, especially against monthly comparisons. It frames the offer as time, not money.

Can I run BOGO on a free trial?

Yes — 'sign up for the trial, refer a friend, you both get a second month free' is BOGO disguised as referral.

What about 'buy two get one free' versus 33% off?

BOGOF (buy 2 get 1) usually wins for items where stocking up is plausible — household products, snacks, refills. The third item being 'free' feels like a windfall.

How do I test which framing wins for my product?

Run the same offer with two ads, identical creative except for the headline framing. 24 to 72 hours of spend should tell you. Use the same audience to keep the comparison clean.

Will BOGO train customers to wait for sales?

Only if you do it predictably. Run BOGO on irregular schedules and tie it to specific reasons (anniversary, restock, end of season) so it doesn't become an expected pattern.

Stop guessing which offer will convert

Pix-Vu generates and tests Facebook ad creative variations against your offer in minutes — not weeks. Upload your product, paste your offer, and get headlines, primary text, and visual variations engineered around proven offer psychology. See it in action at pix-vu.com.