I purchased mobileme at best buy, if i activate it do i still have to pay other fees?

I purchased MobileMe at Best Buy. If I activate it, do I have to pay any other fees? They ask for my address for "billing" but I don't understand why?|||They would need your billing address for special offers and what not. Most paid services on the internet require your billing address, but as you have bought Mobile Me from Best buy you wont need to make any more payments unless you want to upgrade your account in the future that's why they asked for your billing address...