In order to save money this Halloween, why not make your own Halloween Costume from things that you can find around your own home.
You could be a crayon or an oreo cookie from an old cardboard box. You could also use cardboard and aluminum foil to make your own Tin Man costume.
Try using black paint or chalk on a tire and rolling it over a Sweatshirt. You would be "Tired"....Someone else could put on a housecoat, an ice pack and put a thermometer in their mouth and be "Sick". Together you could be "Sick and Tired".
How about taping or glueing some old wrappers onto a white trash bag for a "White Trash" costume.
Here's another easy article on How to Make a Headless Halloween Costume.