Mix and Match BOGO: Pairing Any Two Items

A classic buy one get one offer names one product. A mix and match BOGO names a pool: the shopper picks any two items from a collection and one of them is free or discounted. It sounds like the same offer, and it is not, because the moment the pool holds items at different prices, someone has to decide which unit is the free one. Get that wrong and the offer quietly gives away your most expensive product. This page covers what Shopify's Buy X get Y discount documents about the pool, the one worked cart that shows the price-spread problem, three fixes with their numbers, and how to combine the offer with other discounts. All prices and costs in the examples are assumptions, chosen to make the arithmetic easy to check; replace them with your own.

Same item or any two from a collection

If the offer is "buy this candle, get a second one free," there is one price and the free unit costs exactly what the paid one does. If the offer is "pick any two from the candle collection," the pool decides the cost. The rest of this page is about the second case. The basics of the single-product offer are in BOGO offer explained.

What Shopify documents about the pool

Shopify's Help Center describes the Buy X get Y discount as having two sides. For "Customer buys" you add products or collections to the promotion. For "Customer gets" you add the products or collections that qualify for the discount, and for an automatic discount you choose whether the discounted items are products or collections. The discount type on the get side is a percentage, an amount off each, or free. You can also set the maximum number of times the promotion applies to each order.

The page answers the question that matters for a pool in one sentence: when the same product or collection is in both sections, the lower-priced item that the customer chooses is the item that gets the discount. That sentence, which appears in the steps for automatic discounts, tells you what happens with one shared collection. The page does not say which unit is discounted when the buy side and the get side are two different collections, beyond saying the discount is for the items on the get side, so test any other setup in a cart before you publish it.

Three more facts from the same page shape how the offer behaves:

• Customers must add every item to the cart themselves. The free or discounted "get" item is never added automatically.
• A minimum purchase amount counts products at their full price, before any other discount is applied, and an item that already has another product discount does not count toward the minimum.
• If you give a free product, you need enough inventory for it, because the page warns that customers cannot use the discount if the item is not available.

The price-spread problem, in one cart

Take a collection of five items. Prices and unit costs, all assumed:

The offer: buy any two from the collection, the lower-priced one is free, with the same collection on both sides. Now look at what four different shoppers do.

The discount rate is the same 50 percent whenever the two units are priced the same, and the dollars you keep are not. A pair of A items leaves 4 dollars, a pair of C items leaves 6 dollars (20 percent of the sale, the thinnest share in the table) and a pair of E items leaves 10 dollars (20.8 percent). The lopsided E and A pair is your best result in dollars, 22 dollars kept, because the shopper paid full price for the expensive item. With a shared pool, the pair that decides the offer is the one where both units cost you the most, because that is when the free unit is the one you most wanted to sell at full price.

Now switch the setup. Put the tops in one collection (prices 25 to 35 dollars) and the hoodies in another (prices 60 to 80 dollars), and make the offer "buy any top, get any hoodie free." A shopper picks a 30 dollar top and a 70 dollar hoodie. With assumed costs of 12 and 28 dollars, you collect 30 dollars for goods that cost you 40: a loss of 10 dollars, and an effective discount of 70 percent of the cart's price. This is the version where the free item costs more than the paid one, and it is the one to avoid.

Three fixes

1. Same-price pools. Build the collection so every item sits in a narrow price and cost band. If all five items above were between 28 and 32 dollars, the free unit would cost you about the same as any other and the spread problem shrinks to the choice of which one. The weakness is operational: every new product has to be checked against the band.

2. A cheapest-free rule. Use one shared collection on both sides so the lower-priced item is the discounted one, as Shopify documents, and add a limit on how many times the offer applies per order. The shopper cannot make the free item more expensive than the paid one, but the E and E pair in the table above still gets through at 50 percent. Cheapest item free covers how shoppers learn to game that rule and what guardrails to add.

3. A fixed pair price. Instead of a free unit, charge one price for any two. At 50 dollars for any two from the table above, the E and E pair leaves 12 dollars (50 minus 38) and the A and A pair leaves 36 dollars (50 minus 14). The price no longer depends on which unit is free, only on what the worst pair costs you. The cost is on the shopper's side: the A and A shopper pays 50 dollars for two items listed at 18 dollars each, which is why this fix works best when the items are close in price. The mix and match template is built for this shape; mix and match bundles on Shopify covers the worst-basket test in detail.

Whichever fix you choose, run the table for your own catalog. The pair that decides the offer is the most expensive combination a shopper can pick, and you can read it off your cost column in a minute.

Calling it free

If the second item is called free, the FTC's guide on the word "free," 16 CFR 251.1, applies to the claim. It says the terms of a free offer should be stated clearly and conspicuously at the outset, close to the offer, and that an asterisk footnote does not count. It also says a shopper has a right to believe the merchant will not directly and immediately recover the cost of the free item by marking up the item that must be purchased. A fixed pair price avoids the word entirely. This is not legal advice; confirm the wording with counsel.

Combining with other discounts

Shopify's Help Center says discounts combine only when the setting on each discount allows it, and that product discounts apply first, then order discounts on the adjusted subtotal, then shipping discounts. Two product discounts on the same line item can combine only on the Shopify Plus plan. A mix and match BOGO is a product discount, so a code that also discounts the same items will not stack on a plan below Plus, and if the two cannot combine, the page says the store applies the best discount for the customer's cart. A store can have up to 25 active automatic discounts, and a customer can use up to 5 product or order codes and 1 shipping code on an order. Shopify discount stacking works through those cases.

Building a mix and match set

Open the Mix & match template, which the app describes as "Shoppers pick any items from a set for a fixed price." Choose the collection, set the pair price from the worst-pair check above, and test three carts before launch: the cheapest pair, the most expensive pair and one lopsided pair. The plan requirements for this template are printed beside the button below.