When looking for a used lathe, patience is the name of the game. Continue watching Craig's List every day. Don't forget eBay or any other classifieds that you have access too. All of these really need to be checked daily. The best deals don't last long. The junk is always there. As has been said, stay away from the tubes, look for cast iron ways. A full HP is a really nice thing in your price range, 1.5 HP all the better. Doubt your going to find bigger at your price point. Several of the forums also have classified pages. You may want to put some of them on your daily search list as well.
Hope you find your great deal soon.
Working flat so I can play round,
Repentance Is The