product-bundles-kits

Install Bundler — Product Bundles from the Shopify App Store, create a bundle, and choose fixed, mix-and-match, or build-a-box type. Set pricing as a percentage discount, fixed price, or sum of parts; the app decrements each component's inventory automatically on purchase.

Compute the component sum from current variant prices times quantities, then apply the pricing type: fixed returns a set amount, discount_pct multiplies the sum by (1 - value/100), and discount_abs subtracts a fixed amount floored at zero. Round to two decimals and return savings and savings percentage.

Use apps like Bundler for Shopify or WooCommerce Product Bundles for standard bundles, since they handle split fulfillment, partial availability, and refunds. Build custom only when you need dynamic assembly, real-time pricing, or component substitution beyond app capabilities.

No, WooCommerce requires the official Product Bundles extension. It supports fixed and configurable bundles, per-item or static pricing, optional components, and stock management that caps bundle sales based on component availability.

Inventory deduction fails when the bundle tool is misconfigured or when custom code treats the bundle as one line item. Store each component as a separate cart line item with a standard variant_id and quantity, then test with a real order to verify each SKU decrements.

Re-check availability at checkout by computing available stock as on-hand minus reserved for every component. When something is unavailable, display which specific component is out of stock so the customer can adjust their selection.