The scariest thing about Halloween may be the unintentional expenses. Between costumes, decorations and, of course, candy, the average American will be shelling out $169.81 for Halloween. Altogether, the total amount spent on the spooky season is forecast to reach a record high of $9.1 billion, with 179 million Americans planning to partake in Halloween festivities.

Millennials, in particular, are outspending other generations by about 2-to-1.

Costume purchases made up almost half of Halloween spending, with partygoers spending just over $70 on their disguises. More than $60 will be spent on treats and a little less than $40 on decorations, including the prerequisite jack-o-lantern.

Read more in CNBC.