Found this gigantic piece of cardboard, about 7' x 15', in a dumpster outside an auto body shop. Took it home, slapped a coat of latex on it, hit it with the overhead then traced and painted it. The whole process took about half an hour and used about fifty cents worth of materials.
In some respects, big signs are easier to place than small ones as their size and weight tend to keep them stable, especially if there's a bit of a breeze to hold them against the fence. Never try to work against the wind, especially with large signs. Hanging this sign required a twenty foot walk from my truck, placing the sign directly over two long bungees hooked to the bottom of the fence and then simply stretching the bungees up and out to each side. It took literally less than twenty seconds.
Here's what it looked like at 3:30 p.m. Saturday. It was still up an hour later.