I don't think it's fair to state that the author's cost of living is irrelevant. The author is simply stating how much he/she needs in order to open source the

I don't think it's fair to state that the author's cost of living is irrelevant. The author is simply stating how much he/she needs in order to open source the content. The amount IMHO is immaterial. If you want to donate, then do so. If a sufficient amount of people find the campaign compelling and donate in excess of $20k, then evidently he/she's expected to provide at least that much value to people. If the campaign fails, then clearly the funding goal was too high. To put it another way, people who donate are paying a price based on perceived value. Perhaps someone will offer to write (and make freely available) a similar book for a smaller sum. If not, there is only one offer on the table and the market will decide whether it is reasonable or not.