Almost embarrassing to tell about, but a few years ago a trip to a yard sale advertising "nikon lens" yielded a pristine AI'd 105/2.5 Nikkor and a rare 500/5 Nippon Kogayu (sp?) mirror tele complete with all five filters, caps and leather case.

Two $100 bills in the transaction. I don't feel too guilty about the deal as the seller was a professional birding photographer who was selling out to convert to auto focus gear.