Time for me to give you some decorating ideas for free or really unexpensive costs, seen on the Martha Stewart website.
To start with, some paper lanterns in pumpkin customs ....
... a bats'garland to decorate your fireplace, a door or a wall. To be made with black paper and models easily foundable on the Internet for free. It is also possible to alternate with or replace them by ghosts silhouettes or black cats ...
... a few cans painted with a votive candle inside ...
and don't forget small plastic spiders who climb around your haunted house !