My most recent book chapter on ebooks has just been released.
Ebook publishers, authors, customers, and distributors continue to search for acceptable pricing models. Amazon has tried to enforce sales contracts with authors to give them the best possible pricing and remain the most important distributor of books in all formats. Looking at the recent price of the most popular books, we can see how among all-time top selling books (e.g., Hunger Games, 50 Shades of Gray, etc.), eBooks cost slightly more than paperback – probably due to the price pressure felt by used books. Exclusively hardbound new releases, on average, cost about $3.50 more than eBook versions.

Authors have many choices today. Models include self publishing, direct to distributor, subscription services, publisher wholesale, or publisher agency models – each holding advantages and disadvantages. Such deals can be shaped by negotiations with the distributors or by the type of book.
Self-publishing gives the author greatest control over content but also the most work in distribution. Promoting a book is one challenge, while digital rights management is another especially if the author chooses a free or creative commons model. There are companies that provide support depending on the author’s needs. There is a continuum between self-publishing and direct to distributor.
Direct to distributor: Several distributors will negotiate directly with authors to sell books for a flat fee or royalty. Publishing fees should be proportional to the services provided such as marketing, online stores, and printing.
Subscription-based distribution is promoted by an increasing number of services including Amazon’s Unlimited. These services place a large selection of books. Subscribers can access any for a flat monthly fee. The author may not paid by the book but by the number of “pages” read.
More on Ebooks and other technologies can be found in the latest edition of Communications Technology Update and Fundamentals by Grant and Meadows. https://www.routledge.com/Communication-Technology-Update-and-Fundamentals-17th-Edition/Grant-Meadows/p/book/9780367420161