I had Straight Talk for a few months. I had a Motorola flip phone; I forget the exact model.
As PPs have said, the price is straightforward and the minutes do roll over.
ETA: The internet is very slow, as a PP mentioned, and I never was able to use it. It is not the full internet access like you would get on a smart phone.
Also, the phones are not discounted and you can only use the ones they offer. They don't offer the best phones or free ones because their service is where the discounts are. When I signed up, only 3 phones were available. They have a few more now; some look pretty cool.
ETA: I also had mine on auto-pay. I did not have the customer service troubles that the PP had; nor did I have troubles when I canceled the auto-pay to end my service. Their website was not useful for doing either of those things, however.
I would have kept it, but I really wanted a phone that did more than just make phone calls and texts. I wanted a computer in my pocket. I now have an iPhone 3gs and I love it.
But I do terribly miss the phone
bill I had with Straight Talk.

This AT&T bill is
