Shopify Buy X Get Y simulator
By the Discount Prime team. Last reviewed November 7, 2026.
Pick one of Discount Prime's Buy X Get Y templates, change the group and the reward, and build a sample cart. The simulator applies the rules of the app's checkout discount: whether the cart earns a reward, which items get it, the label each line shows, what the customer pays and the gross profit left after cost per item.
- Customer pays
- $58.00
- Reward value
- $25.00
- Gross profit
- $28.50
- Gross margin
- 49.1%
1 item rewarded (30.1% of the cart).
| Line | At checkout | Reward | Line total |
|---|---|---|---|
| Organic tee3 x $25.00 | Buy One Get One1 of 3 units free | -$25.00 | $50.00-$25.00 |
| Sport socks1 x $8.00 | Not in the offer | - | $8.00 |
| Cart before reward (gross profit $53.50, 64.5%) | $83.00 | ||
This cart keeps a gross profit after the reward.
One cart, three settings
The Buy from collection, get cheapest free template gives the cheapest item free from a group of 2. The cart holds 2 vanilla candles at $22 and 2 cedar candles at $24. Two settings decide what the offer costs you:
| Setting | Items free | Reward value | Customer pays | Gross margin |
|---|---|---|---|---|
| Each product on its own, once per order | 1 | $22.00 | $70.00 | 45.7% |
| Each product on its own, every full group | 2 | $46.00 | $46.00 | 17.4% |
| All offer items together, every full group | 2 | $44.00 | $48.00 | 20.8% |
Once per order gives one free candle, the cheaper vanilla one. Repeating per product gives one free candle of each scent. Counting all candles together and repeating also gives 2 free candles, but both go to the cheapest units, so the offer costs $44.00 instead of $46.00. The repeat setting is the one that moves your margin most, so try it on the carts your customers actually build.
How Discount Prime applies Buy X Get Y
- The group includes the reward
- When the reward comes from the items bought, the number of items in the group counts the reward too. A group of 3 with 1 reward means 3 in the cart and 1 of them free. When the reward is a separate product the shopper picks, the group counts only what they buy.
- Each product, or all items together
- Counting each product on its own needs the full group from one product line. Counting all offer items together lets different products fill the group, and the reward goes to the cheapest eligible item.
- Once per order, or every full group
- Once per order gives one reward group for the whole order. Every full group repeats the reward for each complete group in the cart, up to the maximum rewards per order when you set one. When that maximum limits the rewards, the cheapest eligible items get them first.
- A picked reward is never added for the shopper
- With a specific reward product, only a line the shopper picked as the reward in the storefront offer is discounted. A matching product that is simply in the cart is not rewarded.
- Rewards never go below zero
- A fixed amount off is capped at the item's price, and a rewarded cart line cannot be rewarded again or count toward a second offer.
- Before or after other discounts
- Before other discounts, the reward is worked out on the original price and other offers still apply to the rest of the line. After other discounts, it is worked out on the price left after them. With no other discount on the line, both give the same amount.
What the simulator leaves out
- Other campaigns on the same products, such as volume tiers, bundles and free gifts. The simulator runs one Buy X Get Y offer on its own.
- Customer eligibility (logged-in customers, segments, tags). The simulator assumes the shopper qualifies.
- Discount codes, order-level discounts, shipping and currency conversion. Enter every amount in one currency.
- Shopify's own rounding of percentage discounts by a cent or so on some lines.
An estimate for planning. Test an offer in your store before you launch it.
Build the same offer in Discount Prime
Every scenario above starts from a template in the app. Choose the products, the reward target and how often it repeats, and the offer shows on the product page and in the cart with its own label. Buy X Get Y starts on the Premium plan at $19.90 a month, and Profit Analytics tracks the gross profit of every rewarded order after launch.
Questions merchants ask
In a buy 2 get 1 free offer, does the customer need 2 or 3 items in the cart?
In Discount Prime it depends on where the reward comes from. When the free item comes from the items bought, the number you set is the whole group, reward included: set 3 for buy 2 get the 3rd free, and set 2 for buy 1 get 1 free. When the reward is a separate product the shopper picks, the number counts only the items they buy.
Which item is free when a Buy X Get Y offer gives the cheapest item?
The cheapest eligible unit in the group, counted from the cart prices. When the offer repeats for every full group, the rewards go to the cheapest units first, so a mixed cart pays full price for its most expensive items.
What does Apply once per order mean?
One reward group for the whole order. With items counted per product, Discount Prime gives that one reward to the qualifying product whose reward is cheapest. The maximum rewards per order also counts across the whole order, and when it limits the rewards, the cheapest eligible items get them first. We are aligning the app with this behaviour.
Can a Buy X Get Y offer stack with other discounts on the same product?
Discount Prime lets you apply the reward before or after its other discounts on the same item. Conflict detection covers product discounts. Buy X Get Y joins it unless the offer is set to combine with other discounts. Shopify discount codes follow the combination settings you choose in Shopify.
Is this exactly what my checkout will show?
The simulator follows the rules of Discount Prime's checkout discount for one offer, including the cart labels. Other campaigns, customer rules and Shopify's rounding can change the final cents, so test the offer in your store before launch.
Related guides
- BOGO without losing money: the effective discount of every offer
- Bundles, Buy X Get Y or quantity discounts for AOV?
- Volume discount simulator: quantity and spend tiers on a cart
- Discount profit calculator: margin and break-even for one offer
Discount Prime is our app. The rules come from its checkout discount code and test suite.