Quite honestly, for the $300 price you are talking about, I'd order a dog run from Lowes (10 x 10 which can also be converted to a 5 by 15 if you wish); it's a tad over $200, set it up, add a roof with brace rail clamp, 3/4" PVC pipe and hardware cloth and either attempt to find a small shed on craigslist OR add a large igloo doghouse on the inside as your coop for around another $100 or so.
I've added a picture of one of our runs with the dog kennels just so you can see what the heck I'm talking about regarding the roof.

Gail
I've added a picture of one of our runs with the dog kennels just so you can see what the heck I'm talking about regarding the roof.
Gail