Write Useful Books: A modern approach to designing and refining recommendable nonfiction

by Rob Fitzpatrick

The reason I recommend selling ebooks for $9.99 (as opposed to $20 or $30) is due to Amazon’s definitely-not-price-fixing policy of paying 70% royalties for ebooks priced at $9.99 or below, but only 35% for anything priced higher than that.[44]