Build-a-Box on Shopify: A Bundle Builder Setup Guide

A bundle builder lets your customers build their own box from a list of products you choose, and rewards them with a bigger discount for every item they add. On Shopify, you need a bundle app for this, or a custom build on Shopify Plus. The free Shopify Bundles app makes fixed bundles where you pick the contents.

This guide covers when a build-a-box offer fits your store, how to choose the products and tiers, and how to set one up step by step. For every bundle type side by side, start with our product bundles guide.

What is a bundle builder on Shopify?

A bundle builder, also called “build a box” or “build your own bundle”, is an offer where the shopper picks the contents. You choose the list of products and the discount tiers. The shopper adds items, and the discount rises at each tier.

For example, a candle store might run “Build your candle box”: pick any candles from the list, get 10% off 2, 15% off 3 and 20% off 4. One shopper fills the box with four of the same scent. Another picks four different ones. Both get 20% off.

How is it different from other bundle types?

Mix and match keeps the shape of the set fixed: one top, one bottom, one pair of socks. A bundle builder has no fixed shape. If you want the shopper to fill specific slots, read our mix and match bundle guide instead.

Can you build a box on Shopify without an app?

Not with Shopify’s own bundles app. Shopify says its free app creates “fixed product bundles and multipacks”, where you choose the products and quantities (Shopify Help Center). The shopper can choose variants, but not which products go in.

Shopify also says “the Shopify Bundles app doesn’t support mix-and-match bundles”, and points to two other routes (eligibility and considerations):

• A third-party bundle app. This is the route most stores take.
• The Bundles APIs on Shopify Plus. “If your store is on the Shopify Plus plan, then you can build a custom bundle offering with Bundles APIs.” That means a developer project.

Keep one rule in mind whatever you pick: “Bundles can’t contain other bundles.” Leave existing bundle products out of your box list. For a wider look at native tools versus apps, see our Shopify bundles app vs native comparison.

When does a build-a-box offer fit your store?

A bundle builder works best when customers like to choose, and when many of your products are interchangeable. Look for these signs:

1. Customers already buy several items from one category. Three candles, four snack packs, a few pairs of earrings.
2. Tastes differ a lot. Scents, flavors, colors or styles vary from person to person, so one fixed set would not fit most buyers.
3. Products cost about the same. Similar prices keep the discount predictable for you and easy to read for the shopper.
4. Gifting matters. “Build a gift box” lets the buyer make it personal.

Some example setups:

If shoppers mostly want more of one product, quantity breaks are simpler. If you want to sell one ready-made set, a fixed bundle is faster to set up.

How do you choose the products for the box?

The product list decides how easy the box is to fill and how safe your margin stays. Work through these before you open any app.

Keep prices in a narrow band

If the list holds a $12 item and a $45 item, the box total swings a lot by choice. A percentage discount still works, but your margin per box varies. Group items at similar prices, or run two builders: one for minis and one for full sizes.

Start with a short, curated list

A long list means more scrolling and more decisions, especially on a phone. Start with your best sellers and the products you have the most stock of. Add more once you see what shoppers pick.

Group long lists by collection

If the list spans several categories, group them so shoppers can browse by type. In Sam Bundles, Group by category splits the products into groups based on their collections, so tidy collections make a tidy widget.

Check stock and variants

A box with a sold-out favorite is frustrating. Check stock for every product in the list, and plan what you will do when one runs out, such as removing it from the list.

How should you set the discount tiers?

Tiers are the heart of a bundle builder. Each tier says “buy at least this many items, save this much.” In Sam Bundles, the discount follows the total number of items in the box, and the highest tier reached applies to the whole box.

Use two or three clear steps

The default in Sam Bundles is 10% off 2 items, 15% off 3 and 20% off 4. That pattern is easy to read: each extra item adds a visible step. More tiers mean more labels on the progress bar and smaller jumps between them. Our guide on how many quantity break tiers to offer covers the same trade-off for volume discounts.

Choose percentage off or amount off

Here is how the two compare on a hypothetical candle box with a 3-item tier, using either 15% off or $10 off.

• Percentage off gives every box the same rate. It is the safer choice when prices in the list vary.
• Amount off takes a fixed amount off the box total. It reads well, but on a box of cheap items it becomes a much deeper discount.

Set the deepest tier from your margin

Work out the top tier on the cheapest products in the list, since that is where your margin is thinnest. Our bundle pricing strategy guide shows how to find a safe discount from product cost.

How do you set up a bundle builder with Sam Bundles?

Here is the setup with Sam Bundles, our bundle app. Other apps follow similar steps, so check their docs.

Step 1: Turn on the app embed

Install Sam Bundles and open the Setup guide. Open Enable app embed, click Active app embed, switch on Sam Bundles under App embeds in the theme editor, then save. The install guide shows each screen.

Step 2: Start a Bundle Builder offer

On the app home, scroll to Offers and click Create new offer. Pick a Brand color, then under Other bundle types, click Choose on Bundle Builder. The editor opens with a ready-made offer.

Step 3: Select the products

Under Bundle products, click Select products and choose the items shoppers can add to the box. Tick Group by category if you want them split into groups by collection.

Step 4: Set the pricing tiers

Under Pricing, choose Percentage off or Amount off. For each tier, enter Buy at least a number of items and the saving. Click Add tier for another step, or remove the ones you don’t need.

There is also a Use the product’s compare-at price option, which takes the discount from the compare-at price instead of the current price. Only use it if your compare-at prices are real prices you charged. The FTC’s pricing guides warn against “an artificial, inflated price” set up to make a reduction look bigger (16 CFR 233.1). This is general information, not legal advice.

Step 5: Write the texts and messages

Under Settings, set the Widget title, Description and an optional Banner image (1400 × 350 px is recommended). Then write the three messages that guide shoppers through the tiers:

The defaults read Add {{trigger_amount}} to get {{value_discount}} off and Add more {{remaining_item}} to get {{value_discount}} off. The Bundle summary in the preview shows the messages above a progress bar with a marker for each tier.

Step 6: Set style, placement, schedule and rules

These cards work the same in every offer (offer settings guide):

• Style: match colors and fonts to your theme.
• Placement: turn on Show on included products page to show the builder on the product pages of the items in the list. Choose where shoppers go after adding the bundle: the current page, the cart or checkout.
• Schedule: set a start date and time, and an optional end date for a seasonal box.
• Advanced: tick which Product discounts, Order discounts and Shipping discounts can combine with the bundle. Choose who can use it: all customers, logged-in or non logged-in customers, or customers with specific tags.

Step 7: Save to publish

Click Save. New offers stay Unpublished until you do. To place the widget at a specific spot, add the Bundle Builder app block in the theme editor. The full walkthrough is in the bundle builder user guide.

What happens in the cart and at checkout?

The shopper adds products to the box and sees the bundle summary update: the items, the subtotal, the bundle discount and the total. One click adds the whole box to the cart.

In Sam Bundles, the bundle builder uses a bundle product. At checkout, Shopify’s Cart Transform expands it into the individual products at their bundle prices, so no discount code is needed. Your order lists every item as its own line for picking and packing.

That also shapes your return rule. A simple policy is to refund what the customer paid for an item at its bundle price, not its regular price.

What should you check before you launch?

Run a test order through this list:

1. Fill the box at each tier. Add one item, then two, three and four. Check that the discount and messages change at the right points.
2. Try cheap and expensive boxes. Fill one with the cheapest items and one with the priciest, and check your margin on both.
3. Change variants. Switch size, scent or color and confirm the cart gets the right one.
4. Check on a phone. The list, the summary and the button should all be easy to use on a small screen.
5. Add a discount code on top. Make sure it combines, or doesn’t, as you set in Advanced.
6. Check the order in your admin. Each product should appear with the price you expect.

What mistakes should you avoid?

• A list that is too long. Twenty products in one grid is a lot to scroll on a phone. Curate, or group by collection.
• Wide price gaps. They make amount-off tiers unpredictable for your margin.
• Tiny steps between tiers. If 3 items saves 10% and 4 items saves 11%, the extra item is not worth it to the shopper.
• Fake urgency. If the box is seasonal, use a real end date in Schedule, and keep any timer on the page tied to that date.
• Forgetting the app embed. No embed means no widget.

For the other ways to sell bundles, from fixed sets to BOGO, see how to create bundles on Shopify.