Yeah, look on Gunbroker.com, that is where I baught my used Glock 22 which had been retired from service as they were going to 3rd generation Glocks ("San Antonio Police Department" is stamped on the side). I paid 350 for it, by the time I paid shipping and FFL I spent 400. It came with 3 - 15 round mags. You could also try auctionarms.com for guns.
I was able to compare my Glock 22 with my brother's Taurus 24/7 a while back and loved my Glock more with every shot. His was nice, but mine was lighter and more consistant. I found a .22 conversion kit for the glock i'm thinking of getting, that should be interesting.
Good luck in your search.