Yes its old … Yes its been offered as part of the humble monthly bundle previously … But for those like me who have a back catalog dating back to the 80's and haven't managed to pick it up, this I believe, is the cheapest on steam yet (preparing to be proven wrong) at $11.49. The Complete Edition is $31.32
Speaking of 80's - Stranger Things 3 the game is also 50% off at the moment @ $14.46 … very positive reviews on Steam … not so much elsewhere.
Other notables are The Crew 2 @ $22.48.
YMMV with these but worthwhile checking out the current sale which ends Sep 3rd.