I used Stewart's text at McMaster in '82 as a coil-bound, courier-font tome with hand-drawn diagrams for $10. Steward was my 1st year calculus prof and he was the best math teacher I've ever had. He certainly wasn't rich back then, and if he made shrewd investments with his book income, all the power to him. Remember that the publisher sets the price and profit margin, the author only gets a sliver; fortunately, the book sold well. Publishers are like thieves in the way they force schools to unnecessarily sell a new edition every year.