Contact a chapter near you or your state director, they can point you in the right direction and help steer you away from trouble and buying a pig in a poke.  Generally stay away from craigslist and ebay.  If you do find one, get permission to sample and try it out.  If you can't get that permission, run, don't walk away.  Do some checking with BLM and the county recorder to see if it is currently active and filed with both.