While you "borrow" the books from KOLL, you can't actually buy them from Amazon.com. That is because the Pottermore website, which is the official site for all things Harry Potter, retains the exclusive rights to sales of books. Instead, Amazon.com (and other online retailers such as Barnes and Noble) list the book on their stores and direct customers back to Pottermore.
The Kindle Owners’ Lending Library is just one of the newer benefits of Amazon Prime membership. Amazon.com continues to add features to the service, to attract new users. For example, when Prime first started, members could get free two-day shipping (and lower cost one-day shipping) on most items.
Since then, Amazon.com has added its Prime Instant Video service, which provides unlimited streaming of more than 17,000 movies and TV episodes. The Kindle Owners’ Lending Library, which started small last November, has grown to over 145,000 books.
Amazon Prime costs $79 annually.
Amazon is the only retailer able to offer the Harry Potter books in library format. There is an unlimited supply of each e-book, no waiting list, and you can, as we said, borrow a book for as long as you would like, with the only caveat being that borrowing is limited to once a month.