Well I am definately in the same boat at you....I'm starting my senior year at college, but I've been in my own apartment for 3 years now so I've adjusted. One of my major major staples if you don't have one you should get one....George Forman grill. I use it for everything! And one of the small ones only costs $20. It's worth it.
Ok so here are food staples....I generally go to walmart so a store like that works too
-Frozen chicken breasts or if it's just you chicken breast strips - $5-6 and they last for about 2 weeks or more
-Frozen veggies...not as much money as fresh, but still have the same nutrients according to what i've read. I get broccoli - $3 for a big bag
-Frozen hamburger patties - $4-5 Once you thaw them they taste just as good and you can use a couple to make meatloaf or you can make hamburgers on the george
-Mixed bag of fruit - that way you get quite a bit of fruit at a variety - $3-4
-Bags of lettuce that have different veggies (the ones that have mixed lettuce are the best for you)- $2-3
-Tortillas are good to make different sandwiches - $2
-Huge bags of trail mix at walmart are soo good- $5
-If you like strawberries Kroger's usually does 2/5
-Big packs of turkey or ham 60-70cals for 3 slices i think - $3
-Salad spritzer (dressing spray) I love it - $2 or so
-Granola Bars...personally I like Natures Valley peanut butter so good...but to save I get the off brand generally its like 2boxes for $6 and that definately works for me
-Yogurt get the walmart brand cups I think they are .50 per container.
Also, I don't know where you are but if you have a Krogers in your area look in the ad's for the week (they usually post them at the front of the store) because they have a ton of 10/$10 deals. I've gotten lean gourmet meals for $1 a piece and I love them.
Another thing I found is
http://www.mambosprouts.com/printable-grocery-coupons/ It's a website for coupons for stores near you that you can print out. They are free, all you have to do is sign up. I typed in healthy foods specfically in the google search and thats the site that came up so you may be able to find coupons for kashi.
I'll write more if i think of it. Hope this helps