My university had a free bus system across the city. This removed the need for a car while in school, and saved me a ton of money. Living with roommates also saves a lot, and living off campus in a cheap apartment (still on the bus route) saved a lot as well.
You're in college so let's be honest- if you drink, pregame with your own alcohol before going to the bars, and drink free water at the bars. Waaay cheaper and just as much fun.
Look for obscure scholarships for weird things (I got $500 for being left handed). They have them for hobbies and traits. They might even have a "serving job" scholarship. Google is your friend here.
Look into being a community adviser or residential adviser in the dorms. My university paid a small stipend, and gave free housing + meal plan for CAs. In return, you stay up late a few nights a week on call doing homework, and work the hall desk putting mail in boxes for 5 hours a week. Pretty good deal.
And finally, like tomatops mentioned, STUDENT DISCOUNTS. Tons of places have them, even if they don't advertise them. Ask almost every place you go to if they have one, and always keep your student ID with you.
*edit*
Oh yeah, rent textbooks if you can AND won't need them after college. $200+ textbooks for some "diversity" class? No thanks. $20 rental works for me. My career specific manufacturing textbook for $250? I couldn't buy it used but I reference it nearly once a week at my current job. Worth the cost.