Renting ebooks is cheaper than buying them. So everyone says. But how does the whole thing actually work? If you are renting a digital file, what's to stop anyone from taking screenshots of the pages they are reading and once they're done reading the book, they'll still have the book. Just curious, how does it all work? Is it cheaper than buying a used copy of the book you want [as you can resell the book and get back some of your money]?