Old Cardboard Camel Cigarette Sign

I found this item at an antique shop in Wisconsin Dells, WI this last summer for $20. It is half of a cardboard sign for Camel Cigarettes from the 1940's (according to the seller) that says "It is a fact that Camels..." the bottom captures a portion of the rest of the ad, "are made from". As I stated, it is made of cardboard, and does show signs of aging and wear consistent with an item that is 70 years old that has been cared for and preserved fairly well.  It measures as is 42" long and 18" tall What I'm looking to find out is, how much it is worth, how rare is it, and does the other half of it exist?

Fair