gratuity

nouns

a relatively small amount of money given for services rendered (as by a waiter)
backsheesh, baksheesh, bakshis, bakshish, gratuity, pourboire, tip
an award (as for meritorious service) given without claim or obligation
gratuity
is a type of (narrower)
something given for victory or superiority in a contest or competition or for winning a lottery
"the prize was a free trip to Europe"
award, prize