One Price for the Whole Kit: A Fixed-Price Bundle Without a Kit SKU
How a fixed set price, a 15% margin floor and a published Combo product sold a five-item starter kit without a separate kit SKU.
A Shopify homebrew store sells a five-item beginner kit at a fixed $449 instead of $489 list, without a kit SKU. A Discount Prime Product Bundle uses five specific-product slots and a Fixed set price, splits the saving across the lines, and enforces a 15% profit-protection floor. Publish as a product (Combo) adds a real kit page via Shopify's Bundles API, with inventory from component stock.
At a glance
- Challenge
- A hand-built kit product oversold components that were out of stock, needed manual price edits, and gave customers who owned one item no path to the deal.
- Approach
- One Product Bundle with five specific-product slots at a fixed set price of $449, a 15% profit floor, and Publish as a product (Combo) for its own kit page.
- Discount Prime campaign types used
- Product Bundle
Scenario-based case study: the merchant profile is modeled on patterns across real Discount Prime stores, not a single named customer.
Introduction
A starter kit is the easiest thing to sell to a beginner. It is also the hardest thing to maintain as a product.
Every kit SKU means duplicated inventory, duplicated photos, and a price that drifts away from the sum of its parts the moment any component changes.
The usual planning conversation goes:
"Let's create a kit product and give it a nice price."
A solutions architect asks:
"Is the kit really a sixth product, or is it a price on five products you already stock?"
This case study designs a fixed-price starter kit for a homebrewing store that wanted one clear number for beginners, without a kit SKU to keep in sync.
Merchant Scenario
Consider FirstBrew Supply, a fictional Shopify brand selling homebrewing equipment and ingredients.
| Attribute | Detail |
|---|---|
| Industry | Hobby & Specialty |
| Platform | Shopify |
| Annual Revenue | $980,000 |
| Products | 310 |
| Monthly Orders | 1,400 |
| Average Order Value | $68 |
The five items every beginner needs added up to $489 at list price. The team wanted to sell them together for $449, as one clear number.
Why a Kit SKU Kept Breaking
FirstBrew had tried a kit product. It caused three problems:
- The kit had its own inventory, so it could show "in stock" while the fermenter inside it was sold out.
- Its price had to be edited by hand every time a component price changed.
- A customer who already owned one of the five items had no way to buy the other four as part of the deal.
The kit was meant to simplify the beginner's decision. Instead it created a second, drifting copy of five products.
Business Objectives
| Priority | Objective |
|---|---|
| 1 | Sell the five beginner essentials at one price: $449 |
| 2 | Keep the five components as the only inventory of record |
| 3 | Give the kit its own page, searchable and in collections |
| 4 | Protect margin if component costs rise under a fixed price |
| 5 | Never double-discount a kit that already carries its saving |
Evaluating the Options
Option 1: A Separate Kit Product
A hand-built kit SKU priced at $449.
Advantages
- One page, one button.
- Easy for beginners to find.
Disadvantages
- Own inventory, so it can oversell a sold-out component.
- Price drifts and must be edited by hand.
| Factor | Assessment |
|---|---|
| Architecture Score | ★☆☆☆☆ |
Option 2: Product Bundle, Fixed Set Price Only
Five specific-product slots, Fixed set price of $449, widget on each component page.
Advantages
- Components stay the inventory of record.
- One number for the complete set.
Disadvantages
- No standalone kit page in search or collections.
- Beginners must assemble the set themselves.
| Factor | Assessment |
|---|---|
| Architecture Score | ★★★★☆ |
Option 3: Fixed Set Price Plus Combo
The same bundle, also published as a product with "Publish as a product (Combo)."
Advantages
- A real kit page, inventory managed by Shopify from component stock.
- Works in collections, search and POS.
- No double discount on combo lines.
Disadvantages
- Combo needs specific products, not rule-based slots.
- Publishing is permanent: pausing drafts the combo.
| Factor | Assessment |
|---|---|
| Architecture Score | ★★★★★ |
Comparison Matrix
| Strategy | One Clear Price | Honest Inventory | Own Product Page | Price Drift Risk |
|---|---|---|---|---|
| Separate kit product | ✓Yes | ✕No | ✓Yes | High |
| Fixed set price only | ✓Yes | ✓Yes | ✕No | Low with profit protection |
| Fixed set price + Combo | ✓Yes | ✓Yes | ✓Yes | Low with profit protection |
The Discount Prime Configuration
| Setting | Value |
|---|---|
| Campaign Name | Beginner Kit: Fixed Price |
| Campaign Type | Product Bundle |
| Storefront Title | Starter kit |
| Slot 1 | Fermenter · Specific product · Quantity 1 |
| Slot 2 | Airlock & bung · Specific product · Quantity 1 |
| Slot 3 | Hydrometer · Specific product · Quantity 1 |
| Slot 4 | Siphon · Specific product · Quantity 1 |
| Slot 5 | Sanitizer · Specific product · Quantity 1 |
| Bundle Discount | Fixed set price · $449 |
| Apply | Once per order |
| Profit Protection | Never let this bundle push an item below a minimum margin · 15% |
| If a variant has no cost | Do not discount that item |
| Combinations & Overlap | Best deal wins |
| Storefront Display | Product page block |
| Product Page Layout | Stacked list |
| Publish as a product (Combo) | Enabled · Fixed combo price $449 |
Five specific products. One fixed price for the set. The components stay the inventory of record.
Why a Fixed Set Price Fits
"Fixed set price" is the reward type that says: the set costs this much, whatever the parts add up to.
Discount Prime splits the saving proportionally across the five lines at checkout. The customer sees $449. Each line carries its share. No other campaign type prices a group of products as one number while leaving them as five separate inventory items.
The Combo Switch
FirstBrew also turned on "Publish as a product (Combo)." That created a real Shopify product, built on Shopify's Bundles API, with its own page, its own URL, and inventory maintained by Shopify as the lowest component stock.
It showed up in collections and search, worked on POS, and was grouped at checkout as a kit. The savings were baked into its $449 price, so the discount function skipped combo lines. No double discount.
Eligibility was checked before publishing: at most 30 components, 3 options and 100 variant combinations. Five single-variant products cleared it easily.
Profit Protection on a Fixed Price
A fixed set price has a hidden risk. If a component's cost rises, the fixed price can fall below margin without anyone noticing.
Profit protection checked every variant's Cost per item against a 15% floor. If the set price would push an item under it, the reward was reduced on that item.
Two of the 310 products had no cost entered. "Do not discount that item" meant they were simply left out of the discount, and the builder said so before launch.
Customer Journey
- A beginner finds the kit page in search, sees $449, and buys the Combo product in one click.
- An experienced brewer who already owns a fermenter opens the sanitizer page and sees the stacked-list widget with all five items.
- They add the other four. The set is not complete, so they pay list price, and the cart line explains what is missing.
- A third shopper adds all five components separately. The set completes and the total comes to $449, with the saving split across the five lines.
| Cart | Set Complete | Result |
|---|---|---|
| Combo kit product | n/a | $449, savings already in the price, no further discount |
| All five components | ✓Yes | $449, saving split proportionally across five lines |
| Four of five components | ✕No | List price, progress line shows what is missing |
What a Fixed Set Price Cannot Do
A fixed set price cannot be partially earned. Four of five items in the cart means list price, not "almost $449." There is no proportional reward for getting close.
Once the Combo is published, ownership is permanent. Pausing the campaign drafts the combo product. It is never deleted silently, and it cannot be un-published from the campaign later.
Metrics That Measure Success
- Kits sold per month, Combo and assembled sets combined
- Estimated profit per kit at $449, from real Shopify cost prices
- Lines where profit protection reduced the reward, as a cost-drift signal
- Oversold kit orders, which should fall to zero
- Average order value of kit orders against the $68 store baseline
Common Mistakes
- ❌ Creating a kit SKU with its own inventory, then selling kits that contain a sold-out component.
- ❌ Setting a fixed set price and never revisiting it when component costs change, with no profit protection to catch the drift.
- ❌ Expecting a fixed set price to reward a partial set.
- ❌ Publishing a Combo for a bundle with rule-based slots. Shopify's Bundles API needs to know exactly which variants the combo contains.
- ❌ Leaving "If a variant has no cost" on "Discount it anyway" when margins are tight.
Key Lessons
A kit is a price, not a product.
Keeping five components as the source of truth and letting the bundle define the price removed every inventory and pricing drift the kit SKU had caused. The Combo gave the kit a page without giving it a separate stock count.
Conclusion
Beginners want one number and one button. Merchants want five inventory items that stay honest.
Fixed set price gives the first. Slots give the second. Combo gives the kit its own page without inventing a sixth product to keep in sync.
In this scenario, FirstBrew sold more kits than before, and never oversold a fermenter again.
Frequently asked questions
How do I sell a product kit at one fixed price on Shopify without a separate SKU?
Define the kit as a bundle of the existing products and give it a fixed set price. In Discount Prime, a Product Bundle with one specific-product slot per component and Bundle Discount set to Fixed set price (for example $449) charges that total when every component is in the cart, splitting the saving proportionally across the lines. The components remain the only inventory of record, so the kit cannot oversell.
What does Publish as a product (Combo) do in Discount Prime?
It creates a real Shopify product for the bundle, built on Shopify's Bundles API, with its own page and URL. Shopify maintains its inventory as the lowest component stock, and it appears in collections, search and POS. Savings are baked into the combo price, so the discount function skips combo lines. Eligibility allows at most 30 components, 3 options and 100 variant combinations, and it needs specific-product slots.
Does a fixed-price bundle give a partial discount if one item is missing?
No. A fixed set price cannot be partially earned. In a Discount Prime Product Bundle, four of five components in the cart means list price, not a proportional share of the saving. The cart progress line explains what is missing, but the fixed price applies only to the complete set. If partial rewards matter, a fixed set price is the wrong reward type.
How do I stop a bundle discount from selling below my margin?
Set a minimum-margin floor on the bundle. In Discount Prime's Product Bundle, Profit Protection (Never let this bundle push an item below a minimum margin, for example 15%) checks each variant's Cost per item and reduces the reward on any line that would fall under the floor. Set If a variant has no cost to Do not discount that item so products without a cost are left out.
Can I unpublish a Combo product after creating it from a bundle?
No, not from the campaign. Once a Discount Prime bundle is published as a Combo product, that ownership is permanent. Pausing the campaign drafts the combo product rather than deleting it, and it is never removed silently. Plan the combo as a long-lived kit page, and keep the bundle slots on specific products, since Shopify's Bundles API needs to know exactly which variants it contains.
Go deeper
Run this architecture in your store
Every campaign type in this case study is included in Discount Prime, with profit analytics to verify the margin impact.