Coupon Sherpa has amassed 50 ideas for Halloween costumes for both adults and children that cost nothing--or next to nothing--to make. Here's some with a Curbly bent.
Work of Art: Consists of carry around an empty picture, look-a-like make-up job, optional.
Leaf Blower: Consists of a baseball cap with a leaf dangling from its bill.
Lamp: Consists of an all-black outfit and a lampshade on your head.
Chia Pet: Think duct tape and grass clippings.
To peruse the entire list, follow this link.