Berkeley's eecs department does this. Almost none of the classes have required textbooks, and the prof make sure to mention this on the first lecture so you still have time to return them if you've bought them. They still list the textbooks as references, though, since they may come in handy (eg: [1]). Of course, the book is on reserve in the university library, so even then you don't need to buy it.
Instead of required text books they have lecture notes for most of the classes that are provided free on the website that might as well be a textbook considering how thorough they are (eg: [2]). One or two intro classes had a reader version of the lecture notes, but that was well over 1000 pages, and again, not required since it was provided free on the course website.
For the few classes that did have required textbooks, most of them were books that had been out for at least 3-5 years, so used copies were easily available (eg sicp, K&R C, Vazirani's algorithms, etc.). For the very few classes that had textbooks with a recent version the profs mentioned in the first lecture that the old versions would work fine, but that the students would have to figure out where the assigned reading was if the chapters didn't match up exactly.
[1]: "There is no required textbook for this course, since none is altogether satisfactory, and all tend to be ridiculously expensive. Officially, we'll rely on notes that I provide (on paper and on the web), but many people feel more comfortable if they can supplement this information with other treatments. You might want to take a look at the following books:
Compilers: Principles, Techniques, and Tools by Aho, Sethi, and Ullman—also known as "The Red Dragon Book". You won't need the latest edition.
At least one student recommends Thinking in C++, by Bruce Eckel, which you can download by clicking here.
Python Essential Reference (3rd edition) by David M. Beazley. This is also on-line (see the bar on the left) and at bookstores, on-line and otherwise." - http://inst.eecs.berkeley.edu/~cs164/fa12/info.html
[2]: http://inst.eecs.berkeley.edu/~cs164/fa12/notes/notes.pdf