Pre-paid is the way to go if you don't live on the phone.
I had Cingular Home 50 service (contract) until they raised the price to $30 a month (after taxes, fees and regulatory BS). That was the final straw considering I use the phone only occasionally.
I bought a T-Mobile pre-paid phone at Target a little over a month ago. For $100 I got a Nokia phone with color screen and 1100 anytime minutes that do not expire for 12 months. It's so much cheaper than contract service (again, if you don't gab all day like some people) I don't know why I didn't switch sooner.