Membership Coupon Code?

Hey guys. Is it possible to generate a coupon code for membership? I would like to give a free elite membership ($80 annually) to all book buyers. It would be really cool if I could somehow link the free elite membership signup to the book purchase so that when the book is purchased, there is a redirect to the membership signup at which point they are able to get this at not extra cost.

Otherwise, a coupon code would work fine for now. If that isn't possible with membership, would it work to just have these folks sign up as a free subscriber and from there, I could change their level in admin manually?