I want to upgrade my AT&T cell phone. I have a data package in my phone and i want to upgrade my smart phone. I need to know that does the messaging data plan matter when it comes to me going to a “smart phone” data plan? If not, I only have to pay $18 upgrade fee + $50 for the smart phone. If so, I would have to pay $400 and that would include a 2 year smart phone data plan. I need help and need helpful suggestions. Please guide me and tell me what will be good for me?