We were interested in building a very managable coop to start a small flock. Other than the sides of the run, we didn't have any materials to recycle. In total, the materials for this coop cost approximately $250 at Home Depot - including hardware, paint, roofing, hardware cloth, wood - everything. We put it all together over two weekends. We are amatures! It took us a while to measure twice, so we only had to cut once. It was an awesome family project.
Still some work to do around the base to predator-proof and some finishing touches to apply. But, the majority of the work is done. We have good ventilation at the top and a window in the back. Our clean out door also has a screen door inside, so the whole thing can be opened up in the hot summer months.
We used a solar polycarbonate corrugated roof panel to keep the elements out and the shaded light in.
We modified the coop plans from Purina's Chicken Coop: http://www.salemchickens.com/Purina_coop_plans.pdf