Probably the simplest route, if you have an affiliate site that is already making sales, then you should hit up your affiliate manager with a pay bump request. Many affiliate marketers do this, and then run incredibly successful paid campaigns, with this pay bump as their only real profit margin. Because they have this extra bit of money to work with, they are often given an advantage over other affiliates who did not get a pay bump.
Additionally, you must either include the following disclaimer adjacent to the pricing or availability information or provide it via a hyperlink, pop-up box, scripted pop-up, or other similar method: "Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on [relevant Amazon Site(s), as applicable] at the time of purchase will apply to the purchase of this product." In the above examples, "Details" and "More info" would provide a method for the end user to read the disclaimer.