Yes, COMMAS is a Scrabble word!

Letter values in Scrabble US: C 3, O 1, M 3, M 3, A 1, S 1.

Is it a valid word?

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

a punctuation mark (,) used to indicate the separation of elements within the grammatical structure of a sentence
anglewing butterfly with a comma-shaped mark on the underside of each hind wing

Also: comma butterfly, polygonia comma.