Barnes and Noble "Free" e-books NOT! Internet

We bought our 12-year-old son a Nook for Christmas under the understanding that Barnes and Noble offers 1000's of free books for it on their website. What they don't tell you is that you have to have a credit card on file to order the FREE books. So I bought a pre-paid Visa to be able to open the account, and download free books. BUT then you are not told that the card has to be valid each time you purchase a FREE book from them. The representitive told me "we have to put a $1 hold on your account for each purchase." WHAT for free books, that makes no sense. If they are free then offer them for free, no strings attached. They should tell this to consumers before we spend anywhere from $200-$400. Do you know how many books I could have bought my son for that amount of money, and not have to have told him no two days after Christmas. What an outrage!