collect any older fashioned picture frames you have around the house, and then print out images on your computer to slip inside...old Civil war types, or look for Disney Halloween ones. Also mirrors can be cool. If you have a full length wall mirror, take it down and set it sideways on a shelf or dresser or boxes covered in old sheets. Set candles in front of the mirror, you do not have to light them, but if you spread the spider webs from the candles, to the mirror then up to the picture frames, sets a pretty Haunted Mansion -like scene. If you have games like Oujia Board set those out too. I dea is to use things you already have to cut costs and storage, just put them back where they were when you are done.
Our kids ikedplaying "trade up scaveneger hunt"..they are spli into teams and each team is given a paper clip. They then have to go to houses "trading-up" the paperclip to whatever they are given..they keep going until they have each gotten 5-10 items. My kids decided to have each group make up a scary story involving the item the end up with, it was pretty fun. If you do any apple games, maybe get the most of the apples to be green, like Granny Smitch, then one big, juicy red one, like in Snow White..maybe tie the Old Witch in there some how?
Use a black light, throw as many old white sheets as you can find and borrow over the furniture. We atke the regular light bulbsout of table lamps etc and replace them with black light bulbs for a stronger effect.
Set up a table of Mickeythe Mad Scientist...have cauliflower in a jar w/food coloring to be a brain, (items like ice tongs look funky when in a scientific setting)rubber snakes in another jar, spiders, plastic fingers, gooeyeyeballs from the party store...all for effect.
Have fun, we LOVE Halloween!