Good luck, daniel683104, it is a nice item! I own an original copy of that game, but unfortunaly I don't want to sell it (the spanish edition, so it is not "Teenage Mutant Hero Turtles" (name for the UK original release) but "Tortugas Ninja" (distributed by MCM)), with its carton box and manual including the passwords table. Anyway both the box and manual are in a really bad condition, so I guess it is not an item for collectors anymore, although the game works...
I hope you found anyone out there wanting to trade and having the game in a better condition than mine! Here you have a quick photo taken from my copy of the game, just for the record: