I've been poor for a while now-- Eggs-- cheap protein. Brown rice, not the white which is cheaper, but bad for your diet and lacks vitamins and fiber. Carrots, celery. Oatmeal. Potatoes. Lentils. (I love lentil chili). You can also sprout lentils for a good source of green veggies/salad.

There are something like 2000 varieties of edible plants out there, and people in our modern culture (USA) eat only about 30 varieties. Let me put this bug in your ear:

Depending on where you live, you can actually eat a lot of those plants people call "weeds." Plants like lambs quarters (wild spinach) and amaranth were actually crops and grow all over.

There is actually quite a movement of people who use and eat wild foods and herbs. (I am one of them). Except for the winter, I never am far away from fresh vegetables because I am not afraid of foraging outdoors.

Honestly Pixie,

I'm in the same boat. I don't have a very big budget. I agree with the others- I think that rice, eggs, and beans are all very inexpensive, yet healthy. Brown rice is healthier than white rice.

Ramen noodles, can be a great way to fill up fast, although the nutritional content is not there, other than carbs/sodium - which you do need in your diet. Also, others may not think the same way but I'm a 100% in multi-vitamins. A good quality - ideally organic/natural based supplement can help you quickly, and relatively inexpensively get all your vitamins/minerals/phytonutrients without breaking your piggybank.

Just be sure you're still getting your carbs/protein/sugars. Also, drinking a lot of water helps!

Best,
-Daniela