Well, make no mistake, Amazon gets their cut, even if the book sells for only a penny. The seller doesn’t get all of the 3.99. For a casual seller, they take 99c off the top, and then they add a few incidental fees as well. They do offer another service level, where they don’t charge that 99c and instead charge a $39.99 flat fee every month, but that is only worth it if you sell more than 40 items in a month, which I wasn’t. And I couldn’t hope to compete by raising my sales price above 1c because why would anyone buying consider paying more when they can buy it for a penny? I know that I wouldn’t.
The marketplace they’ve created is just totally rigged against the casual bookseller, which is why I got out.