Krash mentions pawn shops, a great source for low priced 12 strings. My guess is a lot of people get a 12'er, loose interest and need a bit of cash. The local pawn shops have a bunch of 'em.

I picked up a vintage Eko Ranger 12 string, at a pawn shop a bit over a year ago. Great guitar. Big, twangy sound. Not a full time member of the herd, just a visitor.