A service for 7 in Schumann Arzberg Empress Dresdner china would have a value of $120 per place setting or $840 for the whole set
if you were to sell the set on your own. Some sites that I recommend for selling are Varagesale.com, Ioffer.com, Ebay and letgo.com.
Replacements.com will offer you 50% of the sales price on their site as a general rule (not a solid rule).
You can also go to liveauctioneers.com or invaluable.com and search their directory for an auction house near you and consign your set to them.
It is important for you to click the stars after you have read this answer.
This actually is a realistic value of what these pieces are selling for on the secondary market.
I am pledged to be honest and have nothing to gain by undervaluing. I buy/sell these items
as well as attend three estate auctions per month, so I have a good pulse on what the market wants currently.
The market for porcelain is very soft right now because of the change in decorating trends from traditional to
mid-century modern. This and other reasons (flooded market online) have driven the price of antique dinnerware
to lows over the past 5 years.
One must look at sales and not what sellers are asking for items when considering value.
I do hope that better explains my valuation.
Do click the stars after you have read this answer.