The Buy Box is the box on a product detail page where customers can begin the purchasing process by adding items to their shopping carts.
A key feature of the Amazon website is that multiple sellers can offer the same product. If more than one eligible seller offers a product, they may compete for the Buy Box for that product (as long as it can be shipped to the customer's address).
To give customers the best possible shopping experience, sellers must meet performance-based requirements to be eligible to compete for Buy Box placement. For many sellers, Buy Box placement can lead to increased sales.