We have an outdoor woodburner. It burns only wood (which, at the moment, we get for free from FIL's woods) and the burning wood heats a bladder filled with water. The water runs underground and into our basement where it goes into a radiator looking thing. The fans (from the original furnace) blow over this radiator thing and heat the house. Our only gas expense is for our water heater.
Electric is another matter and it's going up too. :(