As illustrated in Compost King's excellent post, great coops can be very affordable. If you have the nonprofit organization Habitat for Humanity in your area, they often have a "Re-Store" where they sell salvaged and donated materials. Otherwise, yes it adds up so fast your head will spin. I didn't keep track on our 8x8 cattle panel coop. We had most of the plywood and the roofing, otherwise it still came out to quite a bit. I don't want to know.