This is a wonderful item. It is an original Calumet Baking Powder Butter and Eggs sign. It was used by store owners to display the price of their wares (and advertise for Calument at the same time). You've probably seen the metal reproductions, but this is the real deal. It is made of cardboard or thick paper, and has the price adjustment wheels mounted on the back.
While there is some yellowing of the paper , mostly around the edges, we consider it to be in excellent condition for the age. It would have been made sometime before 1929 since that's when General Foods bought out the brand as shown in this Wikipedia article.
Why buy a reproduction when you can have an original?