I am interesting in buying a Contessa Nettel Unitak 8x10cm which is in perfect working order has a Zeiss Tessar 12cm f4.5 lens which is all clean and clear and it comes with a case. The seller wants 69 GBP for it, or an offer. How much do you think this camera would be worth?
It is worth what you are willing to pay, isn't it? It is old and they won't have made vast numbers of them so if you want one you probably don't have too much room to negotiate.
If the camera you are after is the one "royalbob" has for sale on Ebay, all I can say is that he is rather expensive for his more common cameras. His Voigtlanders are about three times what I generally pay.