First, you should have a 72 Hour Kit, emergency water, and an auto emergency kit (if you have a car). Parents can help with these items at the beginning of the school year, or you can make your own. When I say emergency water, I am talking about storing bottled water under the bed and NOT using it until the last month of school.
Now let's talk about how you create a Three-Month Food Storage. Stock up at the beginning of each school year, or semester on non-perishable items that can last a long time.
I've created a simple Food Storage for College spreadsheet with some ideas, and you can adjust it based on your needs and preferences. Great for singles not in college as well! Use what you store, store what you use. I'm not sure what everyone likes, so these are just suggestions. All prices are estimates. Store what you have space for. Every situation will be unique, but store something. In the beginning, it will feel like you are spending a lot of money, but if you buy some items in bulk, in the long run they are cheaper than smaller sizes. Ask Mom for Dry Pack cans such as rice, flour, sugar, and spaghetti. It's never too early to start. Good luck!
My niece and her husband on graduation day