Apple app store wants too much info

I have an iPhone 4s where every time that I open the app store it wants my payment info. I want to just download my updates! It says that "there was a problem with a previous purchase" and it won't let me leave and download anything. I'm afraid that if I give it my info that it will charge me for something and I don't want that. I have no idea what is wrong and I don't want to be charged for something I don't even know I had.

DROID

It just needs an update on your payment info, it does that every year 1 or 2 times. But if you are worried about the purchase, then contact apple to get a refund.