Aside from multiple-copy packages and coupons that Leanpub authors can create, customers can themselves set the number of copies they want to buy when they make a purchase, and the total purchase price for a multiple-copy purchase can be greater than $500 (this surprises even some long-time Leanpub authors when it happens!).
The price a customer chooses for the book when they add it to their shopping cart is the "Unit Price". After they add it the book to their shopping cart, they can click the "Edit" button and then set the quantity, which multiplies the "Unit Price" by the quantity. While the minimum "Unit Price" can't be over $500, the total price for a multiple-copy purchase can be greater than $500.
Just as an example, here's what happens if you set the price to be $20 to purchase a book, and then you change the quantity to 100:
(This is just an example - the Leanpub Manual is free of course :slight_smile:)
Here's an article from our Help Center for customers who want to make multiple-copy purchases: