How Much Will My Iphone Bill Be On The Lowest Plan After Taxes

Does any one have the iphone on the lowest plan possible on ATT? At the end of the month whats your total price? It looks like its around $80 but I just want to see if their are an hidden fees or text messaging fees. Im looking to get the lowest level data plan as well. I'm looking to upgrade with the $200 phone. If you have this similar set up please help!!!