How do you create a apple id without a credit card?

If you re on youre ipad/iphone/iPod, (sign out first). Click on a app and tap buy. A pop-up will come on asking to sign up or sign in. Obviously, you would press sign up. After that enter you're personal info and it will take you to the next step. Where it says "Billing" click it, and at the bottom it will say "none". And that is how. :)