I'll post 2 that are on opposite ends of the spectrum.

The first is just ramen noodle soup. It is surprising how delicious it can be when you doctor it up enough! And still very quick and inexpensive. I start by boiling the water (you'll probably want extra water, depending on how much stuff you add) with the flavor packets, then add things in order depending on how long each item needs to cook. For example, fresh carrots need to go in very early (before the noodles), but canned veggies are cooked in the canning process so they can go in at the very end just to get warmed up. To add eggs, whip up the eggs, then at the last minute, slowly drizzle it in to boiling soup while stirring. Here are some of my favorite things to add. You can be creative according to your own tastes!
baby carrots, celery, bok choy, napa cabbage, bean sprouts, jalapeno, canned mushrooms, canned or frozen corn, canned or frozen peas, frozen "chinese vegetable" mixes, cayenne pepper, eggs