Good Morning Dorothy,
Thank you very much for your response,
The prices you looked at on Replacements limited a good staring place for a retail value. If you are looking to resell the Rosenthal Sanssouci pieces you can expect between 40-60% of those retail values. If you are looking to dump the set all at once you would be more than likely looking at between 40-50%. If you have the time and you are looking to maximize your profit on the dishes I would recommend piecing the set out. Making smaller groups and selling single serving pieces can market your pieces to collectors as well as people looking to replace broken or missing pieces. More than likely if you are selling as a large group in an auction setting your dishes are going to go for a wholesale price to someone who is going to attempt to resell the dishes. The current porcelain market is very weak and has been for the past 4 years, a poor economy and low demand have set prices back on the collectible dishes. It can be frustrating for sellers who are entering the market with pieces they have had for a long time and are looking to resell, but there still are some collectors out there buying. You can use a dealer to buy the set but they are going to offer peanuts for it if they offer it at all. I would recommend trying ebay to start as it is very user friendly and attracts a large audience. You may be able to consign with a local dealer who can connect you with other buyers and collectors but just take a good look at the contract before you sign it. Consignment agreements for dishes range from between 25-45%. The dealers may be able to get more of a retail price but you may be paying for that in the consignment fee.
I hope the information was helpful,
best of luck with the dishes,
Frank