The cheapest thing to do is to use only cell phones, but that's a lot of radiation going against your head if you talk on the phone a lot. There is no easy way out. They get you coming and going.
And then you have to decide what to do about your internet connection. You can't do that cheaply with a cell phone as far as I know.
At least if you live in the city, the whole of it is included as local, and you can use a sprint card for all other calls.
What? Been around those exploding gas pumps again?