If I did this right, at the bottom of this is a link to my recent post to the new coop pic thread. We did a similar project to yours. Thankfully we had some rough sawn lumber and metal roofing around the farm that helped keep costs reasonable. We are really happy with the result (and the chickens seem happy!). I think you have a great start and it'll work out great! I look forward to your updates!
Before:
After:
https://www.backyardchickens.com/t/596294/post-your-chicken-coop-pictures-here/4010#post_13736183
Before:
After:
https://www.backyardchickens.com/t/596294/post-your-chicken-coop-pictures-here/4010#post_13736183