Tijuana bibles (also known as eight-pagers, bluesies, gray-backs, Jiggs-and-Maggie books, jo-jo books, Tillie-and-Mac books, and two-by-fours) were little pornographic comic books produced in the United States from the 1920s to the early 1960s. Their popularity peaked during the Great Depression era. The typical “bible” was an eight-panel comic strip in a wallet-size 2.5×4 inch format (approximately 7×10.5 cm) with black print on cheap white paper and running eight pages in length.

Illegal, clandestine, and anonymous, the artists, writers, and publishers of these booklets are generally unknown. The quality of the artwork varied widely. The subjects are explicit sexual escapades usually featuring well known newspaper comic strip characters, movie stars, and (rarely) political figures, invariably used without respect for either copyright or libel law and without permission. Tijuana bibles repeated without a trace of self-consciousness the ethnic stereotypes found in popular culture at the time, although one Tijuana bible (“You Nazi Man”) concluded on a serious note with a brief message from the publisher pleading for greater tolerance in Germany for the Jews.

Most Tijuana bibles were obscene parodies of popular newspaper comic strips of the day, like “Blondie”, “Barney Google”, “Moon Mullins”, “Popeye”, “Tillie the Toiler”, “Dick Tracy”, “Little Orphan Annie”, “Bringing Up Father”, “Dixie Dugan”, and “Mutt and Jeff”. Others made use of characters based on popular movie stars and sports stars of the day, like Mae West and Joe Louis, sometimes with names thinly changed to (presumably) avoid libel. Before the war almost all the stories were humorous and frequently were cartoon versions of well-known dirty jokes that had been making the rounds for decades.
-source: wikipedia.

$10. Each.