Q: Downloading without giving card information

You need to follow, exactly, the instructions on this page when creating a new account : http://support.apple.com/kb/HT2534

If you don't then credit card details will need to be entered before the account can be used to download any item from the store.

e.g. creating an account with 'none'

via a computer's iTunes : https://discussions.apple.com/message/24321860

iOS device : https://discussions.apple.com/message/24700173 (that was on an iPhone with iOS 7, but it should be similar on an iPad with iOS 5)