Trick or Trap, Paperback/R. L. Stine

Scott Harmon would be the kid who is most afraid of everything at his school. That is, if it wasn't for his best friend, Amanda Gold, who is just as easily terrified. They really don't have it easy. Scott's younger sister spends all of her time trying to frighten them. She'll do whatever it takes to get them to scream. Scott and Amanda are also tormented by some neighborhood kids. But this Halloween, Scott and Amanda are determined to get over their fears, even if that means spending time in the creepy old house that everyone else says is haunted. And if Scott and Amanda can stop being so afraid, maybe they can even finally get some revenge...