Many professors, especially those teaching article-heavy classes in the social sciences, skip textbooks entirely, opting to offer course readers instead. Course readers mix together articles, notes and textbook clippings that are directly related to the course. They are updated frequently and cost about $30 to around $80, which compared to the price of a new textbook is cheap–though they can go up above a hundred depending on the course. They are specifically designed for that course, usually by professors, which reduces the cost of wasted, unread pages.
The Stanford Flipside blog has a graphic opinion on course reader prices
Looking from that standpoint, readers seem like an easy, cheap and smart alternative to textbooks. Unfortunately, readers come with as many flaws as they do perks. The largest flaw? They can’t be resold. Textbook retailers are uninterested, and while you might get a few bucks from a future student, but course readers can change each year.
Another very simple flaw is that most of the information in readers can be found online, more often than not, for free. The cost of course readers comes from printing costs, but more than that, reprint fees that professors pay in order to reproduce the article or page in print. But when many news sites have free archives online, and most schools offer some sort of academic journal collection free for students, it’s a tough sell. Couldn’t students just click links for free?