Tree house made from pallets and other scrap wood. We put 2 pallets together for the base and nailed some scrap osb to it for the floor. Braced it up with some scraps of 2x6s. Used a long pallet for the stairs and had some 8 ft land scaping timbers and 4x4s for the poles. Pulled some boards off of some pallets for the side railings. This was completely free for us to make. We just called family and neighbors to see if they had scrap wood and we even got some help putting it together!