Borrow for free from the Kindle Owners' Lending LibraryEligible Prime members can borrow all seven Harry Potter books in any of five languages directly from a Kindle device. There's an unlimited supply of each title, so there's no waiting in a queue to read the book you want.
Buy from the Pottermore ShopFind any Harry Potter book in the Kindle Store to buy from the Pottermore Shop (a third party site). Like all Kindle books, books purchased from Pottermore are "Buy Once, Read Everywhere" and will be delivered to your Kindle or free Kindle reading apps.
How to Borrow for free from Kindle Owners’ Lending LibraryHow to Buy from Pottermore Shop