How can I do this if my phone is still locked with AT&T?
I went to T-Mobil, and the rep gave me a temp phone number, and SIM for $10 to try out their carrier for a day. If I liked it, T-Mobil would switch over my old number, but I did not like it one bit, so I stayed with Verizon. Ask T-Mobil about this $10 try out plan they have.