Frederick Douglass, Sulfur Bitters, the Great Blood Purifier

I bought a Victorian scrap book twenty years ago, because the price was right and the cards were amazing. I had never seen or heard of Victorian trade cards until I bought this scrap book at a yard sale. This one card has Frederick Douglas walking out of a pharmacy with his white wife, advertising Sulfur Bitters, the Great Blood Purifier. Measures 6 3/4 x 8 7/8 inches. The bootblack says "Golly he is going to take de Sulfur Bitters for his complexion." I hope it is appropriate to ask this question on this site. Does anyone have an idea as to the value of this card? Any help would be appreciated. Thank you. By the way, the scrap book cost me just shy of a twenty dollar bill.