Hi Lois....The best way to find what people are asking is to search on ebay with your mark and blue willow. IWC doesn’t offer evaluations, although another collector in here might offer you some insight.
There are also several groups on Facebook you might sell in...one based out of AUS is “WILLOW COLLECTORS - BUY, SELL SWAP WANTED, OFFER INDULGE.”
That might be a way to find someone near where you are.