Our family uses iPhones and the data plan are expensive. So I want to switch to a non-smart phone for all of us, non-smart phones that has bluetooth. Any recommendations? I think it would be better for us to use the iPhones as iTouches.

Also one thing we would worry about is the lack of GPS.

If I changed to T-mobile would I be able to use our iPhones with them without being charged any extra besides the basic plan sans data plan?
Also what could I do about the lack of GPS without a data plan?

See More: I want to escape the data plan with our iPhones.