I just published my first book . And as a member of the Amazon affiliate program, I put an Amazon widget in the book site to get the referral rates by selling my own book.
The “funny” thing is that the referral rate is 6% of the book price which is more than what I get as royalty. Sure, I’m cheating a little bit with the numbers (you get the 6% referral rate in Amazon only after you sell more than 6 copies during the month and the royalties are so low because the book has three authors) but still I find the economics of the book business quite strange.
(and yes, we could have self-published the book to get a higher percentage of benefits, but there were good reasons to go with a known editorial, I elaborate on this here).