Yes, SALES is a Scrabble word!

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

Is it a valid word?

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

income (at invoice values) received for goods and services over some given period of time
a particular instance of selling
the general activity of selling
an occasion (usually brief) for buying at specially reduced prices
the state of being purchasable; offered or exhibited for selling
an agreement (or contract) in which property is transferred from the seller (vendor) to the buyer (vendee) for a fixed price in money (paid or agreed to be paid by the buyer)

Also: gross sales, gross revenue, cut-rate sale, sales event, sales agreement.