Is this the first time that you've tried to download anything from the store ? If it is then unless the instructions on this page are followed when creating an account : http://support.apple.com/kb/HT2534
then credit card details will need to be entered before the account can be used to download any item from the store.
If you are being prompted to review your account then you could see if this post by mountaingoatgirl lets you do so without needing to enter credit card details : https://discussions.apple.com/thread/5295285?answerId=24303054022#24303054022
If not then you will either need to enter credit card details (you should be able to remove the card after entering it), or create a new account, and use the instructions on that HT2534 page when creating it. If you want to use the same email address then you will need to try replacing it on that account first e.g. by tapping on it in Settings > iTunes & App Store on an iOS device, via the Store > View Account menu option on your computer's iTunes or via http://appleid.apple.com
Creating an account with 'none' :
computer's iTunes : https://discussions.apple.com/thread/5729572?answerId=24321860022#24321860022
iOS 7 device : https://discussions.apple.com/thread/5847690?answerId=24700173022#24700173022