This is a small(ish) stove that uses wood scraps, twigs, charcoal, almost anything that burns. Originally designed for third world countries, this stove will boil a pot of water on a couple of 1/2"x1/2" sticks of wood in a pretty short period of time
Much more efficient than burning propane - especially if you're having to boil up lots of beans. Don't forget a pressure cooker!
Get one from Amazon. About $150 with free shipping