The standard legacy publisher contract provides that the author gets 25 % of the net price of a digital book. (twliterary.com)
Beyond the fact that Apple's happy to take advantage of a (much bigger) rival's fight, what's particularly interesting about the promotion is that one of the chief disputes between Hachette and Amazon is over pricing of digital books — Amazon wants to push prices down; Hachette does not. (recode.net)
If you lower the List Price of a Digital Book while it is available for pre-order, we will charge customers that pre-ordered that Digital Book before the price decrease the lower price. (kdp.amazon.com)