BOGO Deals and How to Work Out the Real Discount

You see "buy one, get one free" on a shampoo you already use and it feels like a 50 percent discount you would be foolish to skip. Sometimes it is exactly that, and sometimes the shelf price was raised two weeks earlier so the second bottle is paying for itself. BOGO deals are among the oldest promotions in retail, and they still work on shoppers because the math is hidden in plain sight.

I track prices for a living, and the pattern I see most often is not fraud. It is a promotion that is technically honest but quietly worse than an ordinary discount a week later. Here is how to find the real per-unit saving and when a two-for-one offer genuinely wins.

What BOGO deals actually discount

A BOGO offer is a discount spread across two items. "Buy one, get one free" means 50 percent off each unit, but only if you need two. "Buy one, get one 50 percent off" is a 25 percent discount per unit. "Buy two, get one free" works out to 33 percent off each item, and "buy three, get one free" is only 25 percent.

Those numbers assume the base price is normal. If a shop lists a bottle of laundry detergent at $14.99 for the promotion when it sold for $11.49 the previous month, two bottles cost $14.99, or $7.50 each. That is still a saving against $11.49, but it is 35 percent off, not the 50 percent the sign implies. Run the same check on a "get one half off" offer and the saving can shrink to almost nothing.

How to check whether the base price was raised

The single most useful habit is to compare the promotional unit price with the lowest price in the last 90 days, not with the price printed on the tag today. Here is the routine I use, and it takes under two minutes on a phone.

1. Write down the shelf or listing price of one unit during the promotion.
2. Divide by the number of units you receive. That is your real unit price.
3. Open a price history chart for the same product and size. Note the lowest price in the last three months and the typical price.
4. Compare. If your real unit price is below the 90-day low, the deal is genuine. If it sits between the low and the typical price, it is a fair but ordinary deal. If it is above the low, you would have done better on an ordinary sale.

A tool that keeps that history for you saves the guesswork. Our explainer on how price history tools help you buy at the right time covers which charts are reliable and which ones skip weeks of data.

Online, a BOGO deal often applies only at checkout. Add both items to the cart and read the line total before comparing. On grocery apps the discount often applies to the cheaper of two mixed items, turning "50 percent" into 30.

Watch the size and the brand mix

Many BOGO deals quietly exclude the large sizes, which usually carry the lowest price per ounce. A free 400 ml bottle of shampoo can still lose to a single 1 litre bottle at its normal price. Look at the price per 100 ml or per ounce on the shelf label rather than the pack price. That small number on the tag is the only figure that lets you compare a twin pack, a family size and a single bottle fairly, and it beats any banner.

Why "stock up on BOGO deals" is often bad advice

Coupon blogs love to tell you to stock up whenever a two-for-one appears. I disagree for most households, and the reason is simple: the discount only exists if you use the second unit before it expires, gets forgotten or loses its appeal.

Perishables are the obvious trap: a second loaf in the bin means you paid full price for one. Durable-looking goods age too. Opened sunscreen weakens after about a year, supplements expire and cosmetics separate.

There is also a quieter cost. When I tracked my own grocery spending for six months, the weeks with the most BOGO purchases were also the weeks with the highest total bill, by around 18 percent. The deals were real, but they pulled in purchases I had not planned, and that extra spending outweighed the per-unit savings. Two-for-one offers work best when they hit something already on your list, not when they write the list for you.

The exception is a product you use at a steady, predictable rate with a long shelf life: dishwasher tablets, toothpaste, rice, toilet paper, pet food in sealed bags. For those, a genuine 50 percent offer below the 90-day low is worth buying in bulk, up to roughly six months of use.

When BOGO deals beat a straight discount

Comparing offers is easier when you set a threshold in advance. I use three rules.

• Beat the 90-day low by at least 10 percent. Anything less is normal price movement and will probably come round again.
• Count only what you will use. If you will only finish one unit, a BOGO free offer is a full-price purchase with clutter attached.
• Check returns on the free item. Many shops refund only the paid price spread across both units, so returning one item gives back half of what you paid, not all of it.

Straight discounts usually win on electronics and anything you need only one of. BOGO offers tend to win on consumables and clothing basics such as socks. If you want to know when these promotions cluster, our month by month price calendar marks the seasons when household goods and apparel run two-for-one offers most often.

A worked example from a real basket

Last month a pharmacy ran "buy one, get one free" on a 75 ml tube of a popular toothpaste at $5.29. Over the previous 90 days the same tube had sold for between $3.49 and $4.79, with a typical price of $4.29. During the promotion two tubes cost $5.29, or $2.65 each.

That is 24 percent below the 90-day low and 38 percent below the typical price. A family of four uses about one tube every three weeks, so four tubes would last three months with no risk of expiry. Verdict: a real deal, worth buying in multiples.

The same week, a supermarket ran "buy one, get one 50 percent off" on a branded orange juice at $4.99. The 90-day low was $3.49. Two cartons cost $7.49, or $3.75 each, which is above the low. Verdict: skip it and wait for the regular sale that comes round about every five weeks.

Frequently asked questions

Are BOGO deals really 50 percent off?

Only a "buy one, get one free" offer equals 50 percent off per unit, and only when the base price has not been raised for the promotion. Other versions, such as "get one 50 percent off", work out to 25 percent or less. Always divide the total by the number of units and compare with recent prices.

Can I return just one item from a BOGO deal?

Usually yes, but the refund is normally the paid amount divided across both units. If you paid $10 for two items, returning one typically gives you $5 back. Some shops require you to return both, so read the receipt terms before you open anything.

Is it better to buy two at BOGO or wait for a sale?

Compare the BOGO unit price with the lowest price in the last 90 days. If it beats that low by at least 10 percent and you will use both items, buy now. If not, a regular sale on a single item is likely to match it within a few weeks.