We can tell you that the nation's third largest carrier does have a couple of deals available that will take the price of the starter SIM card kit down to $0 for those with a postpaid account. If you are using a Simple Choice plan, enter the coupon code SIMSALE at check out, and the card is free. If you have a T-Mobile pre-paid account, enter coupon code SIMDEAL and you will be charged only $4.99.
The SIM cards work with unlocked GSM handsets that are compatible with Band II (1900 MHz) or IV (1700/2100 MHz). Phones that meet these qualifications will work on the T-Mobile network. In addition, the SIM cards will work with all T-Mobile branded phones. These 3-in-1, or TrioSIM cards, first rolled out last June.
We don't know how long the two coupon codes will be good for. Therefore, if you need to order the 3-in-1 SIM Starter Kit for your unlocked GSM or T-Mobile branded handset, it is in your best interest to do so now!
source: T-Mobile (1), (2), TmoNews