I don't have a contract, and will never have another one again. When I was on a contract, I hated being locked in when I discovered that AT&T sucks in interior Alaska and couldn't switch without incurring a penalty. (While in Cantwell, I had a signal, but couldn't make a call: They couldn't tell me why. There were at least two more reasons I wanted to switch away.)
I have a vague memory, though, of reading that carriers can get the model of your phone, and will happily add data if they find you're using a smart phone without a data plan. Perhaps I should be more bold.
Right now, I'm paying $30/mo for a local plan, with an older phone. It includes unlimited calling ad unlimited texting with 1 GB of data and fantastic coverage. I don't have a strong incentive anymore for trying to dump the data fees, though I did give it serious thought and eliminated the possibility because of the limitations I perceived.
Do you mind sharing which carrier you use?