Post a book you have that you would be willing to pay-it-forward. Its a good way to get new books to read and declutter some of your book shelves. Don't forget your local libraries are great resources for books.
No selling. Mail using the US postal service and tell the postal clerk it is a book and you can mail cheaper then by weight. I am not sure about other countries. The sender should pay postage and the receiver should later post a book to swap and then pay the postage on that book. So its pay-it-forward, that way no one has to send money to anyone.
