Amazon is the absolute best way. They are considered the publisher by the prison system.
https://www.inmateaid.com/ask-the-inmate/some-prisons-i-think-only-allow-you-to-have-books-mailedshipped-directly-from-the-publisher-this-isnt-something-we-can-do-via-amazon-is-it-does-that-mean-wed-need-to-contact-a-publisher-directly-and-get-it-shipped-under-their-consent-thanks#answer
Accepted Answer Date Created: July 20,2015