For some reason, many college students don't want to wash their sheets. It's like they come to college and forget that mom isn't there to wash their linen, so they avoid doing it altogether.
If you're one of those students, you might want to look into Afresheet.
Featured in the New York Times' "You're the Boss" blog, this fitted Twin XL sheet has seven disposable, peel-off layers. When you notice that your sheets are getting dirty—from eating, drinking, sex, etc.—just simply hold the corners of the top layer, peel it off, and throw it away. Underneath the dirty layer will be a a clean layer.
According to its website, you can by the sheets on Amazon for only $29.95.
So, either buy this sheet that's perfect for the ultra-lazy student, or just wash your sheets like a normal person. Seriously, it's super gross if you don't.