So think I will finally switch to T-Mobile. I currently have a family plan with 2 lines on AT&T. The only thing holding me back is my mom's line which will be out of contract this month, and she wants to get an iPhone after years of using flip phones. My main concern is that I upgraded my line to an iPhone 6. I'm thinking I just need to pay the ETF and ask AT&T to unlock. However I had some issues unlocking my old iPhone 5. I also wonder what is the cheapest plan with T-mobile for 2 lines. I barely use data and currently pay $15 for 200 MB with AT&T. I see T-mobile has the Simple Starter 2GB plan for $45, but can you add another line to that? Any advice on switching carriers would be appreciated.