Solved A Problem
I had a product rebate Visa debit card that was spent down to a small balance.  Really a pain to engineer a purchase to exactly spend the remainder.  Amazon makes it a piece of cake to simply transfer every last cent to an Amazon gift card and then use it on an order with them.  Their system applies all the gift card first and any remaining owed is charged to your credit card.  Sweet!
Rating: 5 stars