1808, Boston, Joseph Bumstead, book dealer, handbill
Originally uploaded by Exile Bibliophile
From this handbill offering book auction services: "Many Books which now lie sleeping on shelves, or buried in obscurity, may in this way be put out of the hands of those who want Cash more than Books- and into the hands of others who want Books more than Cash." And, at no cost to the book owner!
1808, nice and early. I did find more through the Library of Congress to be added to the US Book Trade Index. They have high res scans of these, but the files are too large to upload into Flickr. I'll keep you updated.