Amazon Associates Web Service offers the following operations to find items:
ItemSearch—To find items sold by merchants and sellers. This operation is the one used most often to find items for sale.
SellerListingSearch—To find items sold by sellers. Although ItemSearch returns information about a seller's items (if they are for sale in the Amazon marketplace), SellerListingSearch returns far more information about a seller's items.
ListSearch and ListLookup—To find a customer's list and then the items on that list.
BrowseNodeLookup—To find items associated with browse nodes by navigating through the browse node hierarchy. This operation does not return items directly, only the browsenodes associated with items.
If you do not know whether an item is for sale by a merchant or seller, search first using ItemSearch for two reasons:
Most of the items sold on Amazon are sold by merchants
Sellers often list their items for sale in Amazon's
marketplace as well as in their own stores. Anything sold in the marketplace can be found by ItemSearch.