That would be way too easy to game. I.e. set up an Amazon Marketplace account, "sell" yourself and/or accomplices lots of books for "reasonable" prices, with the money minus some vig including Amazon's charges going back to the "buyers", then they buy el-cheapo Kindle copies.
For sure. Not saying it's a poor choice. As a frequent buyer of used books on amazon, I was interested in the details and thought I would share in case anyone else had the same question.