We all use Tracfone. My DH and my kids don't use more than about 15 minutes a month, so I buy the smallest card possible every 90 days, and the extra minutes roll over.
That's $20 every three months to keep the phone activated, and there are usually codes available to give bonus minutes on top of the 60 minutes I'm buying.
I bought several $10 Tracfones at Target a while back. My kids often manage to lose a phone here and there, so I don't like to spend too much on the phones or the minutes. If I were buying a new phone for me or DH, I would get something a bit nicer than these cheapies.
The one thing to look out for with some prepaid plans is that you buy the minutes and then the company charges an additional $1 fee every day you use the phone. Tracfone doesn't do this--you can use the minutes whenever you like. Their customer service is the absolute worst in the history of the world, so I did some looking around when I was really aggravated with them a couple of years back, and I was surprised by how many of the other companies do charge that per-day fee.