I believe the 99 cent price point tilts the perceived risk / reward ratio to the buyer, while still leaving excellent profits to be made by the writer. (jakonrath.blogspot.ru)
What's the average number of books you can sell @ the 99 cent price point versus the typical E-book price of $ 9.99? (stevescottsite.com)
However, in 2017, the 0.00 to 0.99 cent price point sold the most number of ebooks, followed by the 3.00 to 3.99 price point. (goodereader.com)