Hello Joe, welcome to WAGS. :)
Your skillet, she's a beauty, and an old one. Well, the Blue Book of Wagner and Griswold by Smith and Wafford dates your skillet from 1898 to 1915, and approximate value, in very good condition, 85.00. Like most things though, as far as value, could be more, could be less. The price of cast iron is currently lower than what it has been, and 15 years or so ago, or before ebay anyway, the price of cast iron was signifigantly higher. However, with ebay, them closets, attics, sheds, and old barns are being fleeced, putting a lot more items out there for sale. Hope this helps some. And again, welcome and do be sure to stop back in and see us. :)