IMO, that's a nice fair price. It's not some kind of ridiculous steal that you could later flip for a heap more money, but I would feel pretty good in buying a 909 for three bills if it was in decent shape and fully functional.
It was made in the mid-90s and is a steel slide/alloy frame. The thing I really like about this one that would make some folks avoid it is that it's a slim frame single stack, not a hi-cap double stack. So if you are looking for 12-15 rds of 9mm, this one isn't it. If you are looking for a slim, trim and slender concealable piece, this is a good one if you can deal with a pistol that's a good bit heavier than today's polymer designs.
If you had it and you were in my state and you wanted three hundred for it, I would probably be your buyer. If that's not an endorsement, I don't know what is!