Learn how to make your own food items, such as bread and granola bars, these are really easy to make and will let you create healthy items at low cost. Might be a bit hard if you’re a college student in a dorm, but as long as you have an oven, you’ll be fine. Be careful about intrinsically trusting organic things as being better, it’s a faulty assumption – organic food is not healthier than regular food, especially if you’re talking about additives and artificial junk (which aren’t found in fresh organic nor regular fruits and vegetables).
Hummus and vegetables is a great, great snack. Easy and cheap to make (take one can of chickpeas, add a bit of tahini [ground sesame], lemon juice, oil, and any spices, blend it all up, you’re done!), keeps well in the fridge, is very healthy, and tastes great even kept in a not cold backpack for a few hours. Chop up veggies to your liking (carrots and celery are classics, try broccoli, peppers, cucumbers too), dip in hummus and eat, voila a delicious healthy nutritious cheap snack.
Muesli cereal is also great. It’s basically a combination of grains, nuts, and small amounts of fruit (commonly raisins). The downside is it’s not as cheap as other mass manufactured cereals, but that’s cause you’re paying for quality ingredients like almonds and raisins and not paying for only one ingredient of puffed wheat. I find muesli to be extremely filling and I often eat it in the morning when I need a big boost of energy. Best of all you can make it yourself too.
Basically, the key to avoiding additives and artificial junk is to shop on the edges of your grocery store, and avoid the aisles. Fresh fruit and vegetables, grains, dairy products, all these are healthy and additive-free (for the most part, check the ingredient lists if you’re not sure, such as for things like mass-manufactured bread). It’s when you go down the aisles and see things like premade puddings and Lucky Charms cereals that you start finding additives and artificial junk.
It’s hard at first to stop buying cheap foods like instant pudding, and to buy custard powder and make a fruit custard with milk at home instead. It’s harder if you don’t cook often, it’s sometimes more expensive, and it will take up some of your time. But as long as you remember that you’re providing your body with better quality fuel, it’s easy to resist the temptation to buy pre-made crap. Plus it’s great fun to serve something and say “I made this myself!”