In college, professors leave their dry-erase markers behind.
Which is nice, because I can just take them for free.
I then use them in the under-funded center that I work at, and can actually write things on the board.
Aside from that, college is good for free pens, free printing (even if you do have to wait in line), free paper, and free USBs from the student resource areas, and free money if you can find it on the floor. In college, these are really the little things you have to be thankful for.
Edit: I take that back - last week, outside the train station, I got a free box of candles for Chanukah. These old Chasidic people want to make sure you can light, so they hand out to anyone who looks Jewish - a box of candles, and a cheap-thin metal menorah that would have caught on fire. So, a box of candles is $1.50, I was thankful I didn't have to buy this year and restock.