I have used Tracfone prepaid service for years. I do not use the phone except to have it with me for emergencies and/or to call people when I'm out of the house, but it serves the purpose very nicely. There are a lot of phone models available and they do have text messaging available - something I've never used.
Overall, I know it is a really good deal for me. I shudder when I hear some of the monthly charges people pay for cell phones - especially when I know they aren't using it for anything other than talking.
My minutes always roll over so long as I keep buying minutes. Since I don't use it a lot, I always opt for the once a year purchase of minimum minutes (don't remember what that is) but there are always tons of double your minutes options, too. Again, I don't use those options, but they are there.