Tijuana Bibles (AKA eight-pagers, bluesies) are small (~2x5") illustrated pornographic tracts printed primarily before 1960. The skimpy stories usually framed contemporary movie, sports, political, or cartoon/comic book stars in absurdly hyperbolic sexual situations.
Most bibles consisted of 8 stapled pages. Sometimes you'd get a bonus frame from another title on the back cover, probably a printing mistake. Some were printed in a larger format with 16 pages. Page counts vary, but most stick with the tried and true 8-pager format.
I've never seen a "color" bible. Inside pages are black and white (or shades of such), with an occasional splash of red outlining on the cover.
The "artistic" quality is usually poor-- most feature atrocious grammar with illustrations just good enough to tweak a sexual response. (There are notable exceptions, of course!)
Dated by their subjects, the earliest I've seen have been from the 1920's. The latest set of true bibles (original, underground printings in the traditional form-factor) I've obtained have been from the mid-60's.
There is no definitive answer for this question. Many have presumed a link with organized crime. In my own research, speaking with dozens of individuals who recall the bibles, I've been unable to find any first-hand source. This could very well be due to the "biblical prime" having been so long ago that those involved with original tracts are no longer alive!
Many assume Tijuana Bibles get their name from their place of origin. While some claim to be published in Havana or other exotic locales, it's more likely they were made here in the USA. "Tijuana" has long been associated with iniquity, and pairing it with "bible" produces a fittingly blasphemous appellation.
Your best source for finding original bibles is eBay. Do a search for "tijuana bibles" to bring up a few dozen.
Reprints of bibles are sold through various outlets, either in a deceptive 8-page form, or in published magazines or coffee-table books.
You can also try various collectible sites. Hakes Americana and Collectibles sometimes runs auctions which include tijuana bibles.
Ask your grandpa! Perhaps a touchy subject, asking an elderly man if he has any old pornography, but give it a try. If you're too shy (or squeamish) to ask an old man about his childhood masturbation aids, try your attic, or your parents' attic, or a neighbour's attic.
Many bibles are found unwittingly by collectors of other antiques. The most successful finds are from estate sales, either as part of a paper collection, or (more romantically) hidden inside an old radio or piece of furniture. After all, these tracts are pornography. Where did you stash yours?
To my knowledge, there is no "price guide" for this paper genre-- you can't look up a Fuller Brush Man title in Overstreet. Your best gauge of value is to search eBay for similiar titles. Prices average under $20 per book, with exceptional titles sometimes going for more than $50.
There are three primary considerations: condition, authenticity, and content.
In some cases, a particular author will fetch a higher price. Wesley Morse illustrated a series of World's Fair titles of exceptional quality and whimsical writing, and complete sets in good condition are popular.
You could try eBay, or a collectible site such as Hakes Americana and Collectibles
A single Mickey Mouse and Donald Duck bible went for $504 in a December 2002 eBay auction. I doubt anything but a Disney would have gone that high, and can't imagine any unadorned (eg. signed by Walt Disney himself-- ha!) bible selling for more.
I know of at least one Mexican bible featuring Mutt and Jeff.
Reader "Cisco" writes:
Here in Brazil, during the 60's, there were comics similar to Tijuana Bibles. They were called "Catecismos" ("catechisms") and were all done by a man named "Carlos Zéfiro" who only revealed his true identity in the 90's. There are some of them here: http://www.ludmira.hpg.ig.com.br/galeriazefiro/ZefiroP3GALERIA.htm.