What we would do is put together several large sized cardboard boxes, which my mother would keep just for this activity. We would push them together, weaving them through the living room, making a tunnel of boxes for us to crawl through.
Each of us would have a part of the tunnel to decorate with spooky spiders, cobwebs, flashlights showing monster faces, curtains we had to crawl though and more.
When we finished decorating the fun house, my mother would darken the room and we would crawl from beginning to end, enjoying the scary things that we encountered along the way.
Always the bargain hunter, she would make it a point to go to the stores after Halloween and buy the necessary items to make a scary fun house, but at 70% off the retail value. What we didn't use, would be brought back out the next Halloween.