Going against what others have posted so far, I find that pound for pound meats and dairy are very expensive, and although it may seem cheap stay away from excessive amounts of super processed cheap foods (canned soups, ramen, etc...). you'll want to find the foods with high amounts of fiber (will keep you feeling full longer, and you won't eat as much, and it usually means a good amount of carbs) and protein. Why spend all that money on 3rd rate stew meat for the sake of eating meat? and nutrition wise, for protein, your money would be better spent of things like broccoli and beans, and you save yourself the fat and saturated fat (which is most likely why the meat was so cheap to begin with).
For the best inexpensive high-fiber and high-protein, gotta go with Beans and Lentils (they're like under a dollar a can, and the high fiber content will keep you feeling full longer). Pinto beans offer pretty much a 1g:1g ratio of Protein to Fiber, 1 cup of pinto beans features 11g Fiber and 11g Protein. 1 cup of black beans is about 15g and 15g. and Lentils are 16g Fiber with 18g protein! In contrast, for roughly the same amount of calories, Ramen brings 1g of Fiber (you'll be hungry again soon) and 4g of protein.
Get whatever fruits and veggies are on sale and dry pasta. at $.50 or less a pound, you can't go wrong. A good and easy fresh veggie is Spinnach, if you buy it raw, you can eat it like a salad or cook it down (watch out, Spinnach looses a suprising amount of volume when you cook it down), a good quick tastey recipie is heat a little oil w/ garlic (don't burn the garlic) and toss in a bunch of raw spinich and a pinch of salt, stir occasionally. Spinnach brings tons of Vitamin A, C, Calcium, and Iron. And aslong as you don't boil it, it tastes good. Broccoli is also up there in high fiber, vitamin C, and protein. Good quick way to cook it is boil some water, drop the broccoli in for about 30 seconds and get it out. This way it's cooked enough to get rid of the raw taste, but not so cooked that you loose all flavour. Add some salt and pepper to taste. Then use that already boiling water and cook your pasta.
Bananas, especially when in season, even when not, are always inexpensive. They also contain a good amount of fiber.
Don't really bother w/ a tomato sauce (unless the tomatos and onions are on sale, then make your own) and go w/ a splash of olive oil, salt, pepper, garlic, and tiny amount of lemon juice (you may have to buy the lemons and squeeze it yourself, but for this use, you don't really need much).
As cheap as ramen is, it's typically high in Fat and Saturated Fat, and brings nothing in terms of Fiber, Vitamins, and Minerals. Essentailly empty calories, you'd probably be better off drinking beer for dinner...
canned soups are good in moderation, but dollar for dollar, you get a lot of sodium, but not a lot of nutrients... and after a while, it all starts to taste the same.
for bread, find a local bakery and try to get the day+ old stuff. For cereal, commercial cereal is uber expensive, if you can stand it, get rolled oats and make your own oatmeal in the morning, add stuff like brown sugar to sweeten it up. Peanut butter is a good source of protein, and "good fat" as well. It's moderately priced, will be on the expensive side of stuff I've listed so far.
Pretty much, it's possible to not be hungry, eat well, and eat for very little money, but you will have to sacrifice time. You can find this stuff at any supermarket for not a lot of money and calorie for calorie/pound for pound it's better for you anyway. Stick with these and your body will still be fit for when your bikes show up! Good luck, it takes balls to simply pack up and move away from what you've become so accostomed to!