As this story states, T-Mobile is now reportedly taking any phone as a trade in. Trade in an old phone or buy some crappy old phone and trade that in and sell your current phones on CL. Of course, things seem to change with T-Mobile every day, but at this point, it's crazy to trade in any phone that has value to them.
I did my deal with them on Sunday, and at that point the store would only take certain phones that had value. I went out and bought an iPhone 4 from somebody on CL for $80 and traded that in instead on my unlocked 5S. When I found out yesterday that they had changed the deal to accept any old phone, I called CS and complained that I had spent $80 needlessly, they are crediting me the $80.
----------
Most carriers charge an extra data fee for having a smartphone that is least as much or not more than your monthly payment for a new phone would be with T-Mobile. It really is a no-brainer, unless T-Mobile sucks where you live.
Oh yea, don't get me wrong I see what you are saying. It's just that I have a iPhone 5 and I'm happy with it, and it would just be nice if I didn't have to sell it to get the incentive, that's all.