Yes, BOUNTY is a Scrabble word!

Letter values in Scrabble US: B 3, O 1, U 1, N 1, T 1, Y 4.

Is it a valid word?

BOUNTY is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

payment or reward (especially from a government) for acts such as catching criminals or killing predatory animals or enlisting in the military
the property of copious abundance
generosity evidenced by a willingness to give freely
a ship of the British navy; in 1789 part of the crew mutinied against their commander William Bligh and set him afloat in an open boat

Also: h.m.s. bounty.