I built my 8x4 coop for about 10 dollars. It took, a lot of scrounging, at it is ugly, but it is what I could afford. I collected several pallets. I broke a few apart and replaced the boards to make two solid floor pieces. The walls are all made of pallets- I covered with hardware cloth I had from past projects. Right now the rood is made from fencing. If I can't find more free lumber soon I'll have to break down and buy some. The money I did spend was on screws and hardware. I found great deals at the Habitat warehouse.