Use Bundles to create a customizable build-a-box product where customers pick and choose which products they’d like to include in a fixed-price bundle. The inventory for each individual product is reduced after a box is purchased. When the inventory gets to 0, the individual product is no longer available for purchase on the build-a-box product page.

Set the price of the bundle product at any discounted price you’d like and use the Shopify ‘compare at’ price to highlight the savings. Customers can use additional discount codes at the checkout.