Wear a jump suit (any color). Wear a white Tshirt under the jump suit and have some hand cuffs on one wrist connected to the handle of your trick or treat bag and have fun!
Thanks to Daniel for this easy idea.
Another Idea
Well if you want a cool costume for Halloween you will want to try the one, I did last year, A Prisoner!!!
Just get orange sweat pants and shirt then get fake handcuffs. Then get blue and purple make-up and make a circle around you're eye (you got in a jail fight!!!) and well-a! A prisoner!
Thanks to Kristen for this addition!