http://consumerist.com/2013/06/07/t-mobile-has-a-30-unlimite...
http://www.walmart.com/ip/T-Mobile-SIM-Kit/24099996
http://www.walmart.com/ip/Tmobile-30-Wireless-Airtime-Card/1...
T-Mobile is about the same as Sprint and AT&T, and all are sub-par to Verizon. But what's nice about T-Mobile is that you get unlimited data, whereas with Verizon, you'd better cash in your fleet of 777s to afford your bill.
Sheesh.
Some have good reasons why (mainly coverage, tho TMO is getting better), others are forced to question their contract policy.
Right now I'm paying monthly at TMO what I paid on Verizon+AT&T for me and my wife - except I now get 3 other smartphones on the plan for the same price, all with their own 500M data pool.
Once the new phones are paid off (i.e. equipment loan), I'll be paying just a bit over what I did for just one of my lines for all five lines I'm paying today. And no other carrier in the US has HD Voice.