Ran across this today via the Chronicle for Higher Ed. Textbook Revolution is a collection of online (read free) textbooks for students. Apparently started by a student who was frustrated at paying so much for his class textbooks (what a corporate racket the market is) he decided to take matters into his own hands. The site is impressive in its breadth, although somewhat lacking in the Humanities (but in fairness we use fewer textbooks). At any rate it is probably worth checking out as a way to drive down the cost for your students.
And while we are on the subject Kudos to to Matt Burton whose Wiki book Rhetoric and Composition won the book of the month award. This one is a free Writing Textbook. (I wonder if this counts as a tenure book?) You can check out the larger collection of Wikitextbooks, again read free at Wikibooks.

An appealling notion but it relies on the idea that an online text can simply substitute for the textbook the lecturer wants you to use. First of all reference is likely to be made to chapters and perhaps to printed exercises in the text that won’t have a direct comparison in an etext and secondly of course what is contained (whether in quality or breadth) may not be the same. Considering what students pay for education anyway, shouldn’t they be willing to buy (or share) printed textbooks?
David,
I agree there are problems with the etextbook, but I am not sure they are intrinsic to the medium, but rather are obstacles to be overcome. No ebook can yet substitute in for a printed copy (its difficult to highlight my screen and underline words, not to mention the mess that white out can make on an LCD screen). But perhaps we shouldn’t judge an ebook by the same criteria. For example in a writing class I have in the past required that students by a reference guide. The textbook merely serves as a supplement to the class, not the place from which I get primary material, yet it is nonetheless crucial for them to have. But the online version actually serves this function better (for host of reasons a reference book can be more inclusive, provide wider range of examples etc.) So I would like to suggest it is a matter of context, that these resources can accomplish things a print work cannot, and vice versa. The trick is to figure out how to use each to the best of their respective abilities.
On the notion of price I will say that at least here in the United States the price of public education has risen so much, that at this point I would argue that most public institutions are private, that is prohibitively expensive. I have had students who work two jobs just to pay for college, if I can get them cheaper text books (cut out the middle man trying to turn a corporate profit of their education) I am all for this. This is also paralleled by the problem that in many American Universities the bookstores are increasingly owned by large corporations (for example Barnes and Noble or eFollet) that are profit driven rather than educationally driven. The result is a rise in textbook cost. As another example I know many students who make decisions about which textbooks to buy based on which ones they can get money back for at the end of the semester. I would rather them have a free online resource which they will continue “to posses” rather than one that will be in their possesion for only one semester. Again I don’t face this problem as much as many academics, especially since English is not particularly prone to using textbooks, but if academics can figure out a way to drive down cost to increase accessability I am all for that.