I just recently got my chicks and had been researching the coops here in the Coop Designs page. I have 50 acres but since the coop was going to be close to the house, I wanted it to blend in and look decent. When I finally picked a 8x10 coop I printed off the pictures of the construction and brought it to the local lumber supplier and the cost to build it would have been over $800 and that did not include the roof trusses, windows or doors! This was not a big, fancy coop and I did not have spare lumber hanging around. I ended up buying a used shed for alot cheaper than I could build one for, but still not CHEAP.
I built a 15x20ft run and the cost of that including the 4x4's, hardware cloth, 1x4's etc was around $250. I did enclose the top of the run as well and am glad I did because as soon as the chicks were put out in it, the barn cats were stalking them and scaled it. They were searching for a way in from the top!
I couldn't figure out how to do this inexpensively even after reading all the advise onthe coop design pages but I also don't have any real building skills nor does my DH.
I think the initial outlay can be expensive, but in the long run is worth it. Hope this helps!