I've been using an iPhone 4 on Straight Talk ($50/month no contract). If I decide to switch to an AT&T contract plan, can anyone tell me what the approximate total monthly cost will be? I'm just wondering what kind of taxes and hidden fees there are. When I had Sprint I remember some kind of $10/month smartphone charge. I'm looking at this plan: voice: 450 mins ($39.00) text: none, i iuse google voice ($0) data: 3gb ($30.00) taxes/fees: ??? TOTAL: ??? Thanks.