I found a free wooden crate on my local CL. I spent about another $60-$75 on hardware cloth, nails/screws, tin for the roof, hardware, plywood, and water proofing. The crate is 4'x4'x5' tall.
Here is the crate:
Inside: There is another window on the opposite side.
We still have the pop door and ramp to do and the nest boxes. But since they won't be laying till Spring I have a few more months to do the nest boxes!