He was giving it away free to students, just another attack by creationists. But according to Dunning, it was even sleazier than I'd thought:
For, while the Ray Comfort pages are nicely typeset, well designed, and festooned with illustrations, spacing, bullet points, and indentation, the Charles Darwin part has been forced through some kind of Disneyland supershrink machine. It’s been compressed into a tiny, virtually unreadable font. All breaks have been removed. There is no whitespace at all, except for a double space and a centered title at each of the 14 included chapters (not even a page break!). I don’t consider my eyes to be the worst in the world, but I can’t read it. The font is so small over these long, unbroken lines that I lose my place every time I try to go to the next line. I’d need to use a straightedge to read it, seriously. ...
Was this done accidentally? Was it done to save money? Of course not. It was done to discourage readers from attempting to access the content they tried to purchase; to tie a gag around Darwin’s mouth while Comfort preaches away unrestrained.
Dunning shows examples of this. He's scanned pages from the "Special Introduction" and then from Darwin's text. I'd say it's pretty clear that Comfort didn't want anyone actually reading the Origin of Species.
Well, since it's in the public domain, you can always download it for free from Project Gutenberg. Keep in mind that it's a 150-year-old science book, so it's not exactly designed for easy reading. And as published, they didn't worry too much about white space then, either (but it's not anywhere near as bad as Comfort's version, and you can buy modern editions that are much easier on the eye).
Although this book is the foundation of modern biology, we're learned a lot since then. Darwin knew nothing about genes, DNA, biochemistry, etc. But it's amazing how well scientific discoveries over the past 150 years have just confirmed his theory of "natural selection."
Here's the last paragraph of Charles Darwin's On the Origin of Species:
It is interesting to contemplate an entangled bank, clothed with many plants of many kinds, with birds singing on the bushes, with various insects flitting about, and with worms crawling through the damp earth, and to reflect that these elaborately constructed forms, so different from each other, and dependent on each other in so complex a manner, have all been produced by laws acting around us. These laws, taken in the largest sense, being Growth with Reproduction; Inheritance which is almost implied by reproduction; Variability from the indirect and direct action of the external conditions of life, and from use and disuse; a Ratio of Increase so high as to lead to a Struggle for Life, and as a consequence to Natural Selection, entailing Divergence of Character and the Extinction of less-improved forms. Thus, from the war of nature, from famine and death, the most exalted object which we are capable of conceiving, namely, the production of the higher animals, directly follows. There is grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.