I'm asking just about textbooks that are sold for profit, not free ones. I know journal authors can email their papers or articles free, but textbook? Is Reddit comment wrong?
I ask all subjects like finance, economics, law, not just science.
Science textbooks. When a scientist gets published, he/she doesn't get any profit if the schools use it. Every textbook I've had hasn't been free, so I just email the publisher and find out one of the names (of whom was published) to email them. Since they get no money, they'll be glad to email you back the entire book, to which you can print off yourself. It's a life hack people should know instead of having to pay thousands for college textbooks. Edit: I did this with my Calculus/Geometry professor in ISU (Indiana State University) and he said that he only got one overall pay for being published with other professors, and that he would be glad to give it to me, as he would all of his students. I'm not lying.