For me, the best method is to give TC Gift Card to some who is around us (friends, relatives, colegue,....)
And explaine that they can take, for example, two great e-book for values of this gift.
My sugestion is to give them a links for favorable books, with this prices, and expaline them how to buy without credit cards and cash.
After that, explain them how can buy something else if they want, and you have new member.
