If you go to Kindle or Barnes and Noble you can read descriptions of books and also reviews of readers which I often find helpful. I don't necessarily buy the books there. My first choice is to see if the book is available from our state digital library, but I do buy some and always have books available to read on my Ipad. There are lots of free books available (also out of print, classics and new authors trying to find readers) or less expensive books also. I would also remind anyone using Ibooks, Kindle and Barnes and Noble that you can dl a free sample of the book you are interested in reading, usually the fiset chapter. Love that option.
Diane B