Here are 33 ideas: https://homesthetics.net/33-insanely-smart-eerie-haunted-house-ideas-halloween/
Hi , for inside or outside ?
We did a fun little haunted house in our basement and had one room where the kids wore blindfolds and put their hands into containers with “body parts” using things like peeled grapes for eyeballs and cooked spaghetti for brains. It was simple but they loved how gross it was.
If you are talking inside . Go to a local thrift store and pick up a bunch of plain ( not printed ! ) sheets and use them to drape over your furniture . Like an old abandoned house use lots of spider webbing !!!! Use battery operated candles for lighting . Get a bunch of plastic rate from the dollar store and put them peeking around things , like canisters on counters , next to the toilet , side of couch on bookcases .