The star players in my display are the perennial fall favorites: pumpkins & mums. I bought three big pumpkins at Aldi for only $3 each, and four potted mums at Dillon's for $3 each. I prefer pumpkin painting over carving, but I had already done the black & white thing a couple years ago. This year I decided I wanted to go for the gold instead, so I bought a gold paint marker at Hobby Lobby for about $3.50.
The first thing that came to mind was polka dots, which were simple enough to do freehand (and no one would notice that they weren't perfect circles).