I briefly played a bootleg English translated Green when at a flea market (a market place where people can sell some used/cheap stuff). The lady priced it at $30. This was about in 2002 or so, and I wasn't impressed with it since I already had Red/Blue.
UNFORTUNATELY, I instead bought the bootleg Diamond / Telefang. Oh jeez, the Engrish. I was deceived into thinking it was a rare Pokemon game that I didn't have yet. It's an alright game by itself, but it was not worth $30. :P