Food: Krishna Lunch
The cheapest lunch to be found on campus is "Krishna Lunch", a program run by the local Hare Krishnas here in Gainesville. The lunch has been around for a long, long time - it's now so popular that they had to split the line into two and double their staff just to serve everyone. They set up at lunchtime in the Plaza of the Americas.
For a $3 (might be a bit more - haven't gone in a while) cash "donation" (sometimes the cashier-guy gets uppity when you don't give any money), you get a vegetarian lunch consisting of rice, veggie stuff, salad, a dessert, and mint lemonade. It's quite filling and it's all you can eat, so for the money, it's easily the best food value in town if you don't want to make lunch yourself.
On Wednesdays, they have veggie spaghetti with faux meatballs, which I tend to avoid. And some of the food tastes better than others (their eggplant dish is inferior to most Indian restaurants, IMHO). Additionally, you're sure to get a dose of the insufferable hippie/krishna/peacenik vibe if you sit on the lawn. All in all though, worth a look if you're a UF student or you're driving through Gainesville on a schoolday.