If you have the time and the vehicle then ALWAYS go to the superauctions. You can usually walk out with SOMETHING for $10 or $25. Failing that, then just hang around in the parking lot and talk to people afterwards. Sometimes people buy cabs for the monitors and pull the monitors and leave the rest of the game in the parking lot, and other times people buy too much stuff and have to leave something or sell it for almost nothing to whoever is standing around.
Failing ALL that, if you are just looking for empty cabinets, just talk to lots of people at the auctions, you will likely find someone who lives nearbye who will give you an empty for free.