Man, this is a real hot button issue of mine…but I’ll try to keep it dialed down to “simmer”.
I don’t see that there are any copywrite issues here–it’s no different than selling and purchasing books at a used bookstore, or trading books among friends–but as someone already indicated the university administration may have some conflict here. Analogously, I recall at my Uni that all departments were prohibited from offering products from the Coca-Cola company at any function, even if they were purchased with department (not general overhead) funds, because the food service contract was with a vendor (Marriot, as I recall) that patronized Pespico. (Oddly, the vending machines were serviced by a company that offered primarily Coke products. Weird.)
You might consider using Ebay, Craigslist, or some other existing networking system, as both a way of getting around any administration difficulties and avoiding the effort of setting up a unique distribution system. Alternatively, you might just hold an “Exchange Party”, letting people sign up for the texts they are looking for and swap out with those they already have. I’d be careful about handling any money from both a legal and logistical point of view and just let the students hash it out by barter or private exchange.
One problem you’re going to have with this, though, is that textbook makers routinely issue “new editions” of venerated textbooks, each altered just enough to make it the previous edition unusable; i.e. a slight reordering of pages and different problem sets. In Chemistry, Calculus, and Thermodynamics (all 2 or more semesters) I had to purchase different texts for each semester despite that the relevent classes ostensibly used the same text; and of course, the second set of texts were only available as new. Grrr. I understand that, despite the high prices, textbooks are a rather low margin item for publishers due to the small printing runs and expense of four color or full color printing, but the result is that the student ends up paying $300 or more a semester, and worse, for texts (at least, in engineering and science) that are often overblown, full of factual, typographical, and illustrative errors, and are otherwise not worth $70 or more, for the same information that is presented more succintly and accurately in a $12 Schaum’s Outline (albeit lacking color bombast). If the university had to offer textbooks as part of the tuition fees, I’ve no doubt that they’d change their attitude regarding the cost and issuance of textbooks significantly.
BTW, the campus I went to had an “official and only” bookstore, as most do. Another new/used textbook store established itself right off of campus; buying up and selling used books for reasonable prices (rather than the usurous scalpings the Uni store offered). The Administration, no doubt prompted by the bookstore, quietly asked professors to rotate or select new texts (some did, some didn’t) while refusing to inform the independent store what texts would be used in the subsequent semester. That was, in my opinion, a nasty bit of protectionism, but the independent store managed to get by.
These days, when I want to look up some info on a basic topic or refresh my skill with O-Chem or Statistics, I generally pull out one of the old but serviceable Outlines. On more advanced topics, I still go to standard texts and references, of course, but for the fundamental stuff, it’s just easier than wading through a bunch of four color garbage to get to a derivation. (Feynman’s Lectures are still the bomb, though and well worth the cost in the hardback binding.)