Yes, STEALS is a Scrabble word!

Letter values in Scrabble US: S 1, T 1, E 1, A 1, L 1, S 1.

Is it a valid word?

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

an advantageous purchase
a stolen base; an instance in which a base runner advances safely during the delivery of a pitch (without the help of a hit or walk or passed ball or wild pitch)