Welcome to Just Answer and thanks for your question. Your silverplate service is made by Birmingham Silver Company of Yalesville, CT founded in 1957. They were the successors to Goldfeder Silverware Company. It is silver plated over copper. One 7-piece set of excellent quality is currently for sale at replacements.com for $800. Of course, the value will be less than the retail price and will depend on the current condition. An appraiser would need to see it in person to arrive at a fair sale price. You should check with a local antiques dealer who sells a lot of silver and see who they use to appraise their items.