I want to think my SIL has Virgin Mobile for her daughters. Not sure if that is contract or not. She has unlimited text/data with limited talk. Works well for them. Most of the major carriers have non-contract 'plans' available. See who has the best coverage in your area so you don't run into the 'roaming' situation (if that problem even exists anymore?).
Just upgraded my contract phone to a smart phone today. I added our nephew to my plan a couple of months ago and since I 'upgraded' my plan, I was required to have data on my plan. Neither mine or nephew's phone were data capable. Since my tablet is wifi only, I figured I may as well upgrade my phone to be able to use the data I'm required to pay for anyhow. 6 hrs later and it's still a good thing. Who knows what tomorrow will bring!