EBay is a popular source for Wagner Ware collectors; other sources include Wrinkled Willy Treasures, which specializes in vintage cookware. Garage sales, flea markets and estate sales are also good places to find pieces, with further sources listed at Cast Iron Collector.
In order to be considered vintage, Wagner Ware should be dated between 1914 and 1959. A collector buying from an online seller or antique store should ask for a note of authenticity or other proof of the manufacturing date to ensure the cookware is actually vintage. Wagner Ware collectors typically narrow down their collecting focus rather than buying any piece they find. Because Wagner Ware is so long-lasting and durable, collectible pieces are readily available.