I just bought one of these for $25.00 that I found on Craigslist. Like brand new, unfortunatley we were trying to outrun a storm and darkness when we went to pick it up so I didn't look at it that closely. I was looking for a coop for my 4 bantams. I also knew that would have to do some modifications to make it winter hardy.
Inspecting it the next day, I decided that 2 bantams would probably be happy in it, but no more than that. It's really thin wood. We kept it sitting outside for about a week, next to our 2 coops and runs, trying to decide if we could make it into an addition. We had 30mph winds one of those days, and it blew the roof right off. It is currently in my garage, waiting until next year. We've decided, if, fingers crossed, I get my really nice big coop, that it would be perfect inside the coop, for broodies sitting on eggs, or raising chicks, or those times when you have to separate one due to pecking or an injury. The front side is completely open, with wiring, so everyone could see everyone.
It probably would make a nice aviary. For $25.00, and almost like brand new, I don't think I made a bad deal, even if it didn't work for me right now. No matter what the use, I wouldn't pay more than $25.00 for it.