Hanging traditional wallpaper takes more than the paper: paste, a smoothing tool, often a seam roller. If you already sell those, they belong in the same order.
In Appify Custom Product Options, you link products that are already in your store to choices on the calculator. The customer ticks the extras they need, and each one goes into the cart with the wallpaper as its own Shopify line, at its live price, with its own inventory and shipping.
Here is how linked add-on products work, when to use one instead of a priced choice, and how to set them up.
What is a linked add-on product?
It's a normal product from your store, attached to one choice on an option you already use. Dropdowns, radio buttons, switches, checkbox groups, buttons and swatches can carry one.
The customer never leaves the page to find it. They tick the choice, and the product rides along with the custom item.
Some everyday examples:
- Wallpaper: an Installation extras checkbox group with Wallpaper paste, Smoothing tool and Seam roller, each linked to the product you already stock.
- Flooring: a checkbox group for underlayment and trim, each linked to the product you already stock.
- Gifts: a gift wrap checkbox that adds one wrap product to the order.
Should it be an add-on product or a priced choice?
Both put money on the order. They do different jobs.
| Use a priced choice for | Use a linked add-on product for |
|---|---|
| A service or upgrade, like rush production or a pre-pasted backing | A physical item you stock, like wallpaper paste, a smoothing tool or a seam roller |
| A price that comes from the calculator, such as a rate by size | A price you already set on the product in Shopify |
| Something that is part of the custom item itself | Something you'd also sell on its own, with its own stock count |
Pick one per item. If the paste is linked as a product, leave its price out of the choice's formula or rate, or the customer pays for it twice.
The add-on stays a real Shopify product. Its price, inventory and shipping work exactly as if the customer bought it on its own. No "wallpaper with paste" copies of your products, and no stock you have to count by hand.
What does the customer see?
A normal choice on the calculator. They tick Wallpaper paste the same way they pick a size or a material. On a longer configurator, the extras can sit on a step of their own at the end. How to build a multi-step product configurator covers laying out the steps.
A price with no surprises. The linked product is listed under that option in the price summary, so the cart total is no surprise. If the choice has no charge of its own, only the add-on's price shows on that line.
The full checkout amount, if you want it. Turn on Add-ons and Total with add-ons in the price summary. The customer sees the custom product's price, the add-ons, and the two together.
A quantity they can change. You can let them set how many they want right on the calculator. They can still change it again in the cart.
How many add-ons go in the cart?
You set a default quantity on each linked choice. It's either a fixed number or it matches the custom product's quantity.
- Match the quantity: order the same wallpaper for three walls, and three tubs of paste come with it.
- Fixed number: the smoothing tool stays at one, however many walls are in the order.
A checkbox group can add several products at once. A customer who ticks paste, a smoothing tool and a seam roller gets all three, each as its own line.
What happens in the cart?
The custom product and each add-on sit in the cart as separate lines. The custom line keeps the customer's choices, and the add-on line is the plain store product.
Turn on Keep with custom product in cart to keep them together. If the customer removes the wallpaper, they're offered the option to remove the paste too.
Leave it off for items that make sense alone, like a smoothing tool the customer might already own.
How do you set it up?
You set up add-on products on the choice itself:
- Open the calculator and expand the option, such as Installation extras.
- On the choice that should add a product, like Wallpaper paste, open Add to cart.
- Click Link a store product, pick the product, then pick the variant.
- Set the default quantity: a fixed number, or match the custom product.
- Leave Customers can change quantity on if they should get a quantity field.
- Leave Keep with custom product in cart on if the two belong together.
- Save and publish.
Each choice links one specific variant, such as the 5 kg tub of paste rather than the 10 kg one. To offer both, give each its own choice.
Let Chat with AI build the options first
You don't have to build the option by hand. Tell Chat with AI what you sell: "I sell custom wallpaper. I need wall width and height in feet, a dropdown for paper type, and checkboxes for paste, a smoothing tool and a seam roller."
It builds the measurements, the paper list and the checkboxes. Then you open each checkbox choice and link the product you stock. For more on building this way, read how to build a product calculator faster with Chat with AI.
The custom product still prices itself
Linking the paste doesn't change how the wallpaper is priced. The calculator still works out the wallpaper from its own options: wall size, paper type, panels and a minimum price.
So the wallpaper is priced by the square foot for the wall the customer typed, with a minimum for small walls, and the paste is added at the price on its product page. Each part of the order is priced where it belongs.
If you're still working out the wallpaper side, how to sell custom wallpaper by wall size on Shopify walks through the pricing and the preview.
Where add-on products earn their place
- Wallpaper: paste, smoothing tools, seam rollers, liner paper and a trimming knife.
- Signs and banners: hanging kits, grommet packs and stands. How to price custom signs by size, material and quantity covers the sign itself.
- Flooring: underlayment, trim and adhesive, sold next to a floor priced by the room. How to sell custom flooring on Shopify covers the floor itself.
- Blinds and shades: brackets or a remote you already sell on their own.
- Personalized gifts: gift wrap, a card or a display box.
FAQ
Does the add-on use the price I set in Shopify?
Yes. It's added at its live Shopify price. Change the price on the product and the add-on follows.
Does it track inventory?
Yes. The add-on is a normal Shopify line, so its inventory and shipping work as they do for any other product.
Can one option add more than one product?
Yes. In a checkbox group, each ticked choice can add its own linked product.
Can customers change how many add-ons they get?
Yes. Turn on Customers can change quantity for a quantity field on the calculator. They can also change it in the cart.
Is the add-on included in the calculator's price?
No. The calculator charges for the custom product, and the add-on is charged as its own line. Total with add-ons in the price summary shows both together.
Do I need new variants for "with paste" and "without paste"?
No. The wallpaper keeps its options in the calculator, and the paste stays one product in your store.
Wallpaper and everything to hang it, one add to cart.
Whatever you sell, however you price it · The last options app you'll shop for