I paid 100$ for my used one....there's a couple on eBay....shipping maybe the hard part, I would think you could find someone parting one out around you......I have had the same luck, your not alone.....I was oh I will just replace my strainer....hmm strange, not a drip on fuel coming out.....pulled the strainer what's this? Tar? 20lb of black tar glued to my tank....oh and fuel lines plugged with it....and oh injectors bad oh and the injection pump too....
Mercedes Benz 240D 300D W123 Diesel Fuel Tank 300CD | eBay
Mercedes W123 Diesel Fuel Tank 240D 300CD 300D | eBay