We've had a TracFone for a couple of years. As long as you keep the 'subscription' up-to-date, the minutes roll over and you get to keep your telephone number; or you can let it lapse, then re-activate later, with new minutes and a new phone number. Works great for us, and it seems to have a fairly good roaming network for out-of-state calls.
I like Tracfone too. I have been using it over a year and had no problems. The only drawback is that the minutes expire if you don't buy a new card every couple of months. No big deal though as a 60 minute card is only $20. I have had no technical issues.
I got tired of paying $35 a month with Sprint when I rarely use the phone. I don't have that many friends. ;-) So this works out better and I like not having a monthly bill.
I will get in a plug for Vonage too. For their 500 minute a month plan I pay only $18 a month, nearly $20 less than I had to pay with SBC for basic service.