How much does it cost?
While I'm no expert, and I can offer suggested costs for the development of a single adventure module - since I'm working on my own publication, I am running face on to these costs for a module.
The module I'm looking to create will probably have 25,000 words in it. Had I been hiring a writer, I could expect to pay anything from 3.5 cents to a nickel a word. At 3.5 cents for 25,000 words, that's $875 for just the written part. (Since the primary author is the publisher I am collaborating with, this "cost" is covered in his participation of the project, a cost I am not incurring.)
Since I'm a pro fantasy cartographer, I understand that side of the publishing business very well. My product will have about 12 maps, had I been paying a cartographer to do this, I could expect to pay at least $50 per map, so the map cost is about $600. (Since I'm a mapper, I'm mapping my own for free.)
I'm also playing the role of art director on my project. Because, this is my first publication, many of the artist's are giving me "deals" on art prices, but they've also told me what they normally charge. Cover art, depending on complexity could be anywhere from $150 to $1000, interior art for full color is anywhere between $100 to $500 for a full page color illustration, smaller pieces of art (quarter page, half page) is anywhere from $50 to $150, and B/W illustrations from $25 to $100 each. Art is a great cost in the production of an RPG product. Looking at the above, I can say, by getting deals, I'll have only $500 invested in art, but in other conditions I could easily have spent $2500 or more.
So looking at writing, cartography and illustration only, I've got a sum upwards to $4,000. And we still haven't even calculated the cost of editing, proof reading, and page-layout, all based on hourly rates and variable cost per hour depending on quality and experience.
This describes the cost of single adventure module. If I were talking splat book, the cost is exponentially higher - more maps, more art, more writing, thus more editing, page-layout, etc.
Once all that is done and calculated, generating a PDF is no cost in of itself, well minimal actually, time to crunch making the file I suppose.
Maybe some of my numbers are off, but this is what I'm encountering and I'm actually working to publish a 3 part campaign arc - the above costs are real, at least in what I'm paying.
GP