payoff

A payoff is something you get after investing time or effort into something.

Think about saving money for months to buy that one thing you've been wanting - when you finally get it and pay off the bill, that's a payoff. It can also be a payment or reward you receive from someone, like a bonus at work. Sometimes people use it to describe getting revenge on someone who has wronged them, but this isn't always the nicest connotation of the word.