Google it! You will get tons of hits. There is also Craigslist. You can also join yahoo groups. You really should try to narrow it down to what kind of machine you want and how much you are willing to spend. Even a used setup with rack could start at $7K and go up from there (depending on what features you want and what machine you go with). Additionally you should try and find out if there are dealers in your area for your preferred setup. Many times they get tradeins for people wanting to upgrade or they have demos. I lucked out with my dealer and got their demo machine.