I bought a bank foreclosed home in '05.
Sold it last June.
Once everything was done, I had paid about $12,000 for the trailer and a little over 1/2 an acre.
I sold it to a local builder for $45,000.
If I could find a deal like that, I would do it again in a heartbeat - Deals like that are really hard to find though.
The best way is to scour the paper or know someone that works at a bank that can tip you off when they go to auction.