It seems that US citizens spent some $7.4bn in the run up to Hallowe'en. This included:
- $2.2bn on confectionery ("candy")
- $1.1bn on costumes – for kids
- $1.4bn on costumes – for adults
- $0.35bn on costumes – for pets
That's ~$15 each, on average. Much of this expenditure will have been on imported goods. Then there were all those pumpkins. All good for GDP, of course.