Least expensive cell fone plan

[mr bill]

I have resisted having a cell fone so far and would hope to do so forever more but with kids in pre-school now it looks like I'll have to give in and get one. What I would like to find is a plan that I can have the most basic type of fone with prepaid minutes that do not expire if they are not used within a month or any other set period. or- if not possible the next best/cheapest option. Your suggestons are welcome.

Thanks