This is a common Showalter collectible.  It is a half pint cone.  It is usually purchased as is with no cap, but sometimes a seller will “jam” a cap into the unused cone.  They normally sell for $5–$15 but can go as high as $20.  This cones are similar to their older cousin the buttermilk cones in that they were either used in short supply or not used at all.  They are plentiful and often show up at bottle shows, antique markets, and on the web.