Product Advertising API
Developer Guide (API Version 2013-08-01)

Items for Sale lists millions of items for sale. Most of these items are warehoused and sold by Amazon or other large merchants. All of these items are part of the Amazon marketplace.

In addition to large merchants selling items, individuals and companies also sell items that can be found using Most sellers list their items on the Amazon marketplace.

Product Advertising API operations only enable you to retrieve items that are stored by Amazon. Product Advertising API does not enable you to add items for sale to Amazon. Sellers, such as Amazon Advantage sellers, who do add items to Amazon's catalog do so under a separate agreement. For more information, see Amazon Marketplace Web Services (Amazon MWS).