Reading on Paper Faster than Reading on iPads, Kindles, and Other Digital Devices

A study found that reading from tablets are 10 % slower and people actually like reading from tablets more than from paper. I don't care about the speed of reading as long as I:

1. Get cheaper books in software form
2. Save environment by not buying paper books
3. Get all my books in one place and cleaning out my bookshelves

Unfortunately #1 is not the case  in my surprise. I tried to buy a book from iBooks and it's price was $10 the same price on the same paperback book was on Amazon. I don't get it.