I'm really lucky that I get so much food for free. I haven't been shopping for actual groceries since the second week of school (three weeks ago). This is my guide to eating free in college.
Step 1: Make Friends
Friends will invite you to parties where they have free food. Usually it's homemade too, which makes it a MILLION times better. Also, if your friend has a meal plan some schools allow them to swipe you in so you can use one of their meals. I don't know anyone who has used up all of their meals in a semester, so if you don't mind dining hall food now and then this is a good option. If you don't like dining hall food, you must have never tried the salad bar. Or pizza. Or dessert.
Step 2: Join a Club
Many clubs on campus don't require you to pay dues, and all of the club meetings I've been to have served food. Find something you're interested and go to the meetings to learn AND eat!
Step 3: Don't be Afraid of Lines
If there is a long line at a table or tent, that usually means the food they're giving out is good. It's worth it. Trust me.