Use the Product Advertising API to advertise Amazon products in conjunction with the Amazon Associates Program and earn referral fees when the users you refer to Amazon sites buy qualifying products.
You need to get an Amazon Associates account and ensure that you include your associate tag in API requests. That way the URLs returned by the API contain your Associate tag. When a user visits an Amazon site through a tagged link and buys a product, you earn referral fees. For more information about getting an Amazon Associates account, see Becoming an Associate.