We have 3 cell phones in our house- crazy, I know ;)
2 of them are Tracfone prepaid wireless though and I like them very much.
Basically you buy a phone [most of the time you can find a deal with a free one with purchase of airtime on their website: www.tracfone.com ] and buy airtime cards either online or in many stores like Target, Walmart, CVS, Walgreens, K-mart etc.... The airtime cards will add minutes to your calling bank AND add service time [usually 60 days]. You retain ALL unused minutes aslong as you have valid service time added. You can also purchase a one year card that has either 200 or 400 minutes on it and 1 year of service time for about $90-$100. This will last you all year depending on how much you talk on the phone.
My motorola flip tracfone does not get reception in my house at all but out motorola pocket phone does just fine.
It is really great for those who don't want a contract or monthly bill but want something for minimal usage and emergencies. Most of the time you can also find codes online for extra minutes to use when activating a minutes card actually making it a much better deal than other pre-paid companies.