Here's a quick, healthy, relatively cheap meal I like to make. First, caramelize some onions. Toss in some canned tuna (I like to cook just long enough to get a nice little sear on the bottom). Microwave some frozen broccoli (or some other veggies), toss it all together with some salt and pepper, and serve on a bed of rice.
Also, something even easier: rice (or pasta) with butter and soy sauce. It sounds gross, but I find it pretty tasty. Although, it's best to use good soy sauce. I tried a generic store brand once, I couldn't believe how horrible it was.