I agree with Junnibut that your best bet is to A) use an already built structure that you can get for free or cheap or B) build a structure yourself if you're able.
I purchased this coop
http://www.mcssl.com/store/cumfychickencoops/chaletchicken-coop which retails for about $500. Luckily, I found it for about $200 on Craigslist and drove out to Wisconsin to pick it up. This is supposed to be one of the best brands that you can buy, and it's still pretty poorly made. The doors stick, the nesting box door has broken many times, the wood has cracked in several places, the sliding door to close the girls into the coop at night stick if there's ANY debris in them at all. The "easy pull out" flooring is anything but easy to pull out, and it's overall poorly designed, constructed, and executed. We've had it since April of this year, and have had to make MANY adjustments over the past 7 months. I think it will last a couple of years, but only if we're very careful with it.
I would also like to add that the coop & run looks pretty big in the picture, doesn't it? Well, it isn't. It's tiny. I wouldn't leave 2 chickens in there, let alone the 4 it suggests. We built and attached an additional run onto the coop that measures an addition 8'Lx 3'W. We also allow the chickens to free range in the backyard most days. I only recommend allowing them to free range once they KNOW that you are their protector, and will come to you when called. Otherwise, it can be a real P.I.T.A. to get them back into the coop. I have ONE new hen that doesn't allow me to hold her, catch her, or come too close to her, and she makes getting them back into the coop a chore EVERY-SINGLE-TIME LOL.
Junnibut- Where are you located? I'll gladly give you a few scoops of feed to try out on your girls. That should be enough to know whether or not they care for it. I also have plethora of corn (it was $9 for 50 lbs at TSC!) if you'd like a couple scoops of that as well
Cheers!