There have been lots of "paying it forward" projects online and sometimes it pays off. There have been several authors who have offered free ebooks that I downloaded and liked well enough to pay for some of their other books. If you find a way to reach an audience, and have a good product, with others available to back it up, it can work.
Check out Mark David Gerson, for instance, or an old (but not in years) member who once posted here frequently, Malcolm Camp[bell.