One was left wondering at the true magic of that Halloween — namely, at the transforming effect of something as simple as the opportunity for free exchange, for the chance to derive mutual benefit from the difference in tastes between individuals.

In this, at least, Halloween was all about treats, and, despite what the opponents of the exchange economy will tell you, there was no trick about it anywhere you looked.

https://mises.org/mises-daily/halloween-and-its-candy-economy