Site Builder: Buy Button does not Display for All Items in the Web Store

If the Buy Button is not displaying in the webstore and it has been determined that the customization of the item layouts/templates is not the issue, it could be the incorrect setup of the webstore. 

1. Navigate to Setup > Site Builder > Set Up Web Site.
2. In the Setup tab, set the Web Site Scope field to Full Web Store.
3. Click Save.