Cell phones only here too. I've been that way for years now. I've been using
Republic Wireless for about a year now. No contract, buy the phone up front ($150 or $300), and
plans from $5/month to $40/month depending on what you want. I currently am on an older plan of theirs which is $20 per month for unlimited talk/text/data (3g). I am incredibly happy with the service. They basically highly encourage you to connect to wifi, and when you have wifi it makes a voice over IP call instead of using the cellular network. This saves them (and thus you) a bucket load of money. When you don't have wifi, it uses the Sprint network. If Sprint signal isn't there, it uses Verizon's network.
If you happen to be interested in switching, they do have a referral program. You can get $20 off your first bill (and $20 off mine). PM me and I can get you a link.