Each of the first 115 cards in the 1939 Play Ball set can be found with red overprinting on the back indicating sample card status...
Collectors will pay a small premium for a type card of a common player. Sample cards of most star players will sell for about double the price of the regular-issue cards, while DiMaggio and Williams samples sell for about the same price as their regular-issue cards.2011 Standard Catalog of Baseball Cards -- Lemke
You could count the total number of sample cards that I have seen on eBay on one hand. This, and the 1941 Play Ball Paper variation are two obscure, and incredibly rare variations. Think of what kids did when they got these cards. Something with a red stamp on the back of their card? Right in the trash. The scarcity of these cards are unknown, but some information has been gathered about how this card was distributed in 1939. This promotional advertisement card was handed out at ballparks and other such venues to create excitement for their new Play Ball gum cards and product.
I think I got this card at a great price, and I'm very happy with it. Also, please comment and share this blog/story with whomever you feel would like to follow it. Let me know if you would like to see more videos in the future, or if I should stick to scans.