whenever i try to download a free game it tells me to go to my payment info and whenever i try to put in the cards code it always says "the code is invalid", and i can only update the apps i already have can you please help me with my problem
I'd guess either the credit card or gift card funding the account isnt' any good. Or maybe you're typing a number wrong. You can, in your iTunes profile, set it to 'no card'. I can't tell you how to do it off the top of my head, but there is a way to have no card attached to iTunes.
One the iPOd go to the App store app. Scroll to the bottom of the page and tap on yur Apple ID, then tap on View Apple ID. You then have to enter your password to get to your accont where you can edit the account, including payment method.