I was really happy that a calculus professor of mine told everyone that they could buy an older edition of this book if they wanted, and he would supply his own

I was really happy that a calculus professor of mine told everyone that they could buy an older edition of this book if they wanted, and he would supply his own homework problem sets as handouts rather than depend upon the ones in the book. For the reading assignments, his syllabus listed page numbers for the past three editions, so everyone could keep up. For $25 I was able to buy a copy two editions prior, which was what pretty much everyone else in the class was using too. Of course this doesn't help actually solve the problem, since someone else had bought that book for $200 and they then saw it depreciate by $175 when they sold it to me used.