On Leanpub, people often choose to pay for books they can get for free, to show support for the author and the project!
Sometimes people will even get a book for free, and then pay for a second copy later, if they want to support the author. (For more information about our "variable pricing" model, and how people can choose to pay what they want for books and bundles and courses on Leanpub, please go see this article.)
We also make it really easy to get refunds within 60 days of any purchase, in case people change their mind, or realize they could have had it for free, and they only found out about that later.
If you want to, you can also choose to give any royalties you earn from supportive readers to a cause by going here:
...making sure to replace YOUR_BOOK with your book's unique web address.
Also, please note that we don't force refunds on people at the author's request; it typically makes people unhappy if we do things like that!