If you use the code GIMAG on theeca.com (found in an article of the new Crackdown GI issue), you can receive a free, full 1 year membership (I think it's only for new accounts). You do need a credit card to sign up, but if you cancel before the 1 year is up, you won't be charged. This is a great deal for the free amazon discount. Be sure to use the coupon soon, because the article doesn't mention the expiration for the coupon.
I just signed up.
Normally it's $19.99/year fee for membership to theeca.com but with that code it's $0.00 and you get benefits, one of which is 10% off video games (the actual games, not hardware) and I THINK music game bundles. There are other benefits too but I haven't checked them out yet.
Just gotta make sure you quit when/before a year is up.