How about a blockchain based e-book system? Each copy of a book is like a coin in a cryptocurrency. I would love to see this direct to authors, but other 'rightsholders' will get in the way. Regardless, when a sale is made it is tracked through the blockchain. The market sets the prices. So, if you bye hot new thriller for $20, the seller gets a cut as does the storefront. Then, if you transfer that book, a small percentage of your sale goes to the original author. If you give it to your uncle ernie for free, well you transferred ownership but not money, so nothing trickles upwards.
This system would allow everyday people to sell used ebooks at whatever the market would bear. The downside is in a system like this, reading habits are traceable by all. However, if you wanted to buy "IEDs for terrorist Dummies" you probably wouldn't want to use this system.