You can buy a new cell phone if you want, and put it into your unlocked phone. Or you can just buy the
SIM seperately and not waste your money on a phone you wont use. You can use any
GSM carrier in your phone. Best if your phone uses both
GSM 850 and 1900. What kind of phone, and where will you use it? Zip?
If you want tmobile check there online coverage tool to make sure it will work for where you need it. You said this will be for an emergency phone. Tmobile prepaid may not give you coverage in the boonies. But if the coverage will work they are one of the best deals going in prepaid. If you wand to buy a phone for the
SIM, Target and walmart sell a tmobile nokia 6010 for $40. If you wanted you could buy the phone, use the
SIM and sell just the phone on ebay to recoop some of the money. Or you can go to a tmobile store and pay way too much ($40 plus) just for the
SIM. Or you can buy the same exact
SIM on ebay for $6-11 shipped and comes with 60-150 starting minutes. If buying off ebay buy from someone with lots of positive feedback. I have done this for a prepaid tmobile
SIM and have been very happy.
You can also buy other
SIM's from other companies in the same way. Avoid Cingular Gophone at all cost. They are way too expensive unless you need lots of in-network calling or want to pay for really expensive prepaid data.
If you want cingular's network use a cingular MVNO such as Oxygen
GSM or Beyond Wireless
GSM. Same network with much better plans, rates, and expirations.
Although NOT compatable with your phone, Net10 uses many different networks (Cingular, Tmobile, and others combined). 150 min/month=$15/month, always 10cpm, no roaming charges. The largest prepaid
GSM network available, since this will be an emergency phone too. Phones start at $40 and come with $30 of airtime. No activation fee. Text=$0.05 in and out.