One of Spielberg’s first, and a really good suspenseful movie.
Watership down can be read at bedtime. As can Stephen kings childrens book the eyes of the dragon . The Eyes of the Dragon - Wikipedia
“Goonies”. How has no one mentioned “Goonies”? About a group of kids, a treasure hunt, has some scary moments but a happy ending.
You could save some dough, just yell “BOO!” at them randomly.
Your kids ain’t seen scary movie til you see Phantasm. That’ll get your kids screaming. 
Tangent question: What about some good, Halloweenish animation? (Particularly cartoon shorts.)
I’ve got a notion to project some video on my garage door for part of my Halloween night setup, and I’m looking for ideas of things to show. I’m thinking clips/shorts, because the ToTers aren’t going to hang out watching them for long.
Here’s our October animation Dvds the kid watches every year:
Monsterhouse
Paranorman
The Nightmare Before Christmas
Frankenweenie
Coraline
If you’re trying to scare the ever-loving crap out of your trick or treaters, try this one “The Cat with Hands” and this one “The Separation”.
On TCM tonight at 8:45 Eastern.