Yes, PERQUISITE is a Scrabble word!

Letter values in Scrabble US: P 3, E 1, R 1, Q 10, U 1, I 1, S 1, I 1, T 1, E 1.

Is it a valid word?

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

an incidental benefit awarded for certain types of employment (especially if it is regarded as a right)
a right reserved exclusively by a particular person or group (especially a hereditary or official right)

Also: fringe benefit, exclusive right.