This is a simple, cheap costume that my aunt came up with and it has won 3 contests-2 adults and one childrens.
Garbage Goddess:
Large black trash bag
clean "trash" (milk jugs, snack wrappers, cheese bags, etc)
twist ties
black hair spray
pull "trash" out of your garbage, clean it up and staple it to the garbage bag
spray hair black
bunch hair up and put twist ties in hair
LOOKS GREAT!!!