Welcome and congrats on striving for a cleaner and healthier lifestyle!! (I don't like the word diet, having a word that shouts DIE at me isn't very soothing)
Some tips that helped me when I began my whole foods plant-based vegan lifestyle, although I'm way beyond college age, and then some, lol, are shopping at the "ugly tables" in the produce area (the discounted section where damaged/bruised/already ripe produce is marked down), catch frozen fruits and veggies on sale (the dollar tree stores in our area carries frozen fruits and such for $1/bag), try to buy in bulk as much as you can and break it down to store and cook in batches if you have the space and access to a kitchen.
I found mung bean noodles at an International grocery for like $4 for a dozen individually wrapped packs. All you have to do is add hot water and soak for like 7 minutes, then you can add whatever sauce or seasonings you like. Toasted sesame oil is a good thing to have on hand if you want the noodles to have a Chinese take-out kind of flavor. It doesn't take much to add a whole lot of flavor.
Make salads ahead of time and keep in a large ziploc baggie to eat from all week. Keep cans of chickpeas and bags of shelled hemp hearts on hand to top off the salads. Be mindful of salad dressing ingredients or try to make your own. I used to drizze lime or lemon juice on mine instead of using the high fructose corn syrup, etc. filled typical store bought dressings. Prep the veggies and fruits the day before, or one day a week, to make it easier to grab and go, otherwise you resort to the same old choices out of convenience.
Oh yeah, and check your peanut butter labels, too. I was blown away by how many add sugar and palm oil, etc. Check on you tube, as well. There's a lot of advice for eating vegan while attending college. Good stuff!
There's soooooo many other things, too, but those are what came to mind immediately. Best wishes in your tasty new adventures! Be kind to self no matter what you choose and remember to try to think of it as enriching your life, not taking away from it. (not to mention lessening the negative impact on the animals and environment overall) I found that to be a huge help as I was used to living in an environment that continually fostered a feeling of lack.
"Strange times are these in which we live when old and young are taught falsehoods in school. And the person that dares to tell the truth is called at once a lunatic and a fool." ~Plato