Charles Crowell writes a valentine to Amazon’s e-reader as a cost-saving tool for cash-strapped college students:

If we extrapolate these savings from these two courses over a
two-semester, ten-course academic year, we could expect an average
savings of $245.05. That number, of course, would vary according to the
cost of the respective textbooks, their number, the number of textbooks
in a Kindle format, and the Kindle version price of those textbooks.
Lots of variables, but my point here is that there are some budgetary
savings available from a traditional pedagogical approach
to using the Kindle. As textbook publishers put more and more textbooks
into formats that can be read by eBook readers of any type, the savings
should be larger. I’ve modeled prospective savings in a traditional,
textbook-based pedagogy, and the savings would appear to be on the
order of 50 percent per year. Over four years of undergraduate school,
that’s a savings of several thousand dollars. — Inside Higher Ed