A $3.00 dollar venetian blind and some scrap material turned my son into a winner at two local costume contests with this Peeping Tom Costume.
I used an old book back with the collapsible handle and wired them so that the stayed in the up position. I then attached the blind, which I had cut down to a more workable size, to the handles. My son wore a long black "drench coat", (it was actually a friends black dress jacket), a pair of brown socks and black shoes, he wore shorts under his jacket so that his bare legs were showing.
I also made a window sill out of cardboard and glued that onto the bottom of the blind, on the window sill sat a few miniature items. Last but not least I made the curtains and glued them into place. While trick or Treating he would say. "PEEK a boo."
This was one of the fastest and cheapest costumes I have made yet.