I have recently found a way to get unlimited minutes from a sprint cell
phone. What you do is you get a sprint plan with a feature called
sprint to home. What this allows you to do is, set a number that you
can make and receive calls to one number(sprint would like this to be
your home) but I have found if you use this service called voicestick
which you can get at http://www.voicestick.com/ it will work around
that.

what voicestick is a VOIP company with unlimited USA for $20 and
Unlimited Global for $25. I call the UK for about 40 min a day and
about 2 hrs of the US

Voicestick has a cellular bridge feature that when you dail from your
cell phone it gives you a dail tone. So you can have unlimited minutes
on your phone. Then as far as incoming you would give out that
voicestick number and it would forward to your cell phone. So as far as
sprint knows you are just calling your home or your home is calling you.

Unlimited calls in and out. It  saves me about $50 or 60 a month.