Vintage Pearl Necklace Question

by JULIE
(Cary, NC)

Hello ~ I recently acquired a vintage pearl necklace at an auction and I am not sure how to price. The necklace clasp was Gold tested at 18k, pearls are graduated and hand knotted - approx. 16" in length. The clasp has a stamp that says 18KS and there is a stamp of an arrow going through a circle next to that. I am not sure at what price to sell this item on EBAY. Any help is greatly appreciated!