$350-$400 new, so I'd say you found yourself a good deal. Have you shot one of these before? You'll see alot of people HATING the trigger, but once you shoot it a bit you won't even notice it. Primal has one in 9mm, and my father has the 40. They are a great shooter and there are things to make that trigger a little smoother. I'd pick one up at that price if I had the funds available.
That sounds like a good/great deal depending on what comes with it. If you get a bunch of hi-cap mags and a hard case, jump on it. If just the gun and 1 magazine, it's an alright deal and I'd probably buy it if I were you.