Playing cards have been around for over 100 years, but it wasn't until recently that I discovered people actually collect these cards just for their designs! It seems that it's a collecting craze and people actually swap them. I probably wouldn't know a valuable card if it were laying in front of me, but I did just purchase 3 on eBay simply for their beautiful graphics. My reason for purchasing them is not to start another collection, but to copy them to use for jewelry cards in the store. I really like the way the earrings show on these cards...much more than the generic earring cards.
The more desirable cards are usually sold as singles or doubles on ebay for an average of $1-3 each. I will eventually have them copied on card stock, but for now I photocopied and applied them to manila tags. We are also using them to display pins and some necklaces. I especially love this Deco lady and bird. I can see where one could easily get swept up in collecting a certain category of cards. My favorite would definitely be the art deco era.