I suppose I could start ordering ink in huge amounts and then spending all my time trying to sell it on campus.
00inkjets gets me 25% cash back on MrRebates as well as purchase miles on the full spend.
In fact, I have bought a brand new snowboard with gear as a result of 10% off gc.com converted into $1000 REI certs. With a few discounts and some dividend, I'm selling it used at a profit: about 6000 miles and $0.