At Leanpub, our 'variable pricing' model allows authors to set a suggested price and a minimum price for their books. As a reader, this allows you to choose how much you want to pay, by moving the pricing slider to the left or to the right when you're making a purchase. It also allows authors to offer their books to readers with different capacities to pay. This means an author can offer a book for a lower minimum price (they can even set the minimum price to zero, making the book available for free), but also encourage readers to pay what the author thinks the book is worth at the suggested price. Many Leanpub readers actually choose to pay more than the minimum and even the suggested price, usually because they want to show extra support for the author. To be clear, you get the same book or package as anyone else, regardless of what you choose to pay.