You can search for advertisements in the database American Periodical Series Online (1740-1930). Click on "Document Type" and select "Advertisement." The database includes digitized images of the pages of American magazines and journals published from colonial days to the dawn of the 20th century.
Images from historical newspapers can be searched through the Library of Congress.
Also, take a look at the website, AdAccess, from the Duke University Libraries.
If you would like further assistance, please Ask-A-Librarian.
