Smart Phone without data plan? Possible?

I have an I phone but I cannot afford it. I was told that I could buy a new phone and change my plan to only voice and messaging (that way I would avoid cancellation fees) I want to know if I can buy a smart phone and put only the voice and messaging on it. They will cut the data on my I phone and switch my plan to only messaging and voice which will save me a bundle; but later, if I want, they can add the data back and use my I phone. Apple I phones are different they say. Can anyone help me on this? (I was told to buy a Go Phone at the store and I would rather not do that).