I am unable to catalogue this stamp (if it is a stamp) in Scott's Germany (states), etc. If any Germany experts reading this post know of this stamp's identity and value, I'd truly appreciate your replies. Thanks!
According to a listing on another site, it is a Hamburg private local post issued during the 1870s and 1880s by C Hamer & Company. Per the asking price (about $2), it doesn't appear to be valuable in a monetary sense.