What is Amazon’s buy box? Simply put, it’s the place on the product page where the default seller and 3 other top sellers appear. Amazon takes into account things like price, seller rating, inventory availability, and fulfillment options
[1] when determining which sellers end up in the buy box and which don’t. Depending on the source you consult, somewhere between 82% and 90% of all sales on Amazon are from sellers in the buy box. Clearly, it’s a reasonably competitive space for retailers.