I have an essay in progress about this model. My central thesis is that the most correct pricing model (in terms of ethics and economics) is one which compensa

I have an essay in progress about this model. My central thesis is that the most correct pricing model (in terms of ethics and economics) is one which compensates the author's time to create a work. If I can write two books in a year and a reasonable wage for my experience and expenses is $80,000 a year, each book needs to earn about $40,000 to justify me continuing to write. Divide that by the number of readers to figure out the amount of profit I need to make per unit. I can justify giving away the electronic version and soliciting donations on theory that free redistribution from countless readers will reach a much larger potential audience for print sales and donations than I could possibly reach, especially with my marketing budget. Besides that, doing so appeals to my sense of ethics. Many, many people contributed to making Perl 5 and many, many people helped me write the book.