Do I have to enter my billing information in order to use my apple id and install twitter on the iphone5?

I am trying to install Twitter on the iphone 5. After signing in to Twitter, I try to install the app. I then get asked to sign in with the Apple ID. I do that. So far, so good. Then I get a message saying: This Apple ID has not yet been used in the iTunes Store. I click on "Review" but then get asked for billing information. I don't want to enter it, since Twitter is a free app. What to do?