Yes, THRIFT is a Scrabble word!

Letter values in Scrabble US: T 1, H 4, R 1, I 1, F 4, T 1.

Is it a valid word?

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

any of numerous sun-loving low-growing evergreens of the genus Armeria having round heads of pink or white flowers
extreme care in spending money; reluctance to spend money unnecessarily

Also: parsimoniousness, penny-pinching.