i have apple id but can not dl from appstore free app

What happens when you try to download something ?

You can use an iTunes account for downloading free items, but unless the instructions on this page were used when creating an account :http://support.apple.com/kb/HT2534

then you will need to enter credit card details (which you should then be able to remove) before the account can be used to download any item from the store

Do you mean 'account has not been used in the iTunes store' ? Have you logged into your account on your phone by tapping on it in Settings > iTunes & App Store and reviewed your account's details ? Unless you followed the instructions on the HT2534 link in my above post when creating the account then you will need to enter credit card details before you can use the account to download any item.