When tricks of any kind are used to fool or deceive someone, especially for financial gain, that's trickery.
If you suspect that a cute kid has scammed you out of twenty dollars, you have every right to accuse him of trickery. Trickery is using pretense or sleight of hand or fast talking to cheat a person out of some amount of money, the way a card sharp or a con man might do. The earliest use of trick was in this negative sense — a mean ruse or cheat. Trickery simply adds the Middle English ery to the end to form a new noun.