Griswold cast iron cookware is no longer manufactured and is considered a highly collectible antique, so the pricing is not fixed and very subjective depending on the age and condition of the item, its rarity and the seller's motivation. There are some buying guides online, including Antique Trader and eBay.
Vintage Griswold skillets, depending on condition, can range from around $50 to over $700, as of 2015. Many of the buying guides caution shoppers that there are a large number of fakes and reproductions for sale on the market that have almost no value at all. They show users identifying indicators with logo stamping and other features that can help avoid a bad purchase.
There are several collectible cast iron skillet brands; however, Griswold is considered the most sought-after. There are books about Griswold cookware, its collection and valuation available at online booksellers including Walmart and Amazon.com. The Antique Trader website also has a book for sale on cast iron cookware collecting.
"The Book of Griswold and Wagner" claims to be the definitive resource when it comes to this type of cast iron antiques. It purports to have updated pricing guides and market values, as well as over 1,000 photos to help in identifying Griswold items.