old furniture can be made into a coop too! drawers for nest boxes! Armoires already have doors that open (for easy coop cleaning) and some have clothes hanging bars that can be roosts, get creative! The chickens don't care what it looks like if their needs are met.
I know others have mentioned Craigslist, my favorite sections to peruse are the "free" section and the "farm and garden" section. Browse the photos, lots of things can be used for purposes they weren't intended for.
The wire fencing was my only substantial expense to my build and one of the...