Yesterday, I saw 2 catalytic converters being sold at flea market for $25 each. I guess they were removed off junk cars.
If they are worth $100 each, you should of bought them and sold them for the profit, but then you might of been the one nailed for trying to sell something that was stolen, although I don't think they have serial numbers, so it's basically impossible to trace them back to any car they came off of. Maybe serial # on catalytic converters is the answer to eliminating the theft problem, if you could trace them to the cars they came off of and the theft had been reported, you could stop the thieves in their tracks.