Here is a great idea for making a very simple yet totally delicious soup.
Cook up a mess of your favorite greens. ( I grow and use Kale . . . read why by clicking here.)
Do not add any salt or butter, just cook them in water.
When tender, drain some water if necessary, but leave enough to retain a brothy consistency.
Next open a jar of your favorite salsa and add enough of it to flavor your greens.
That's it! It is that simple! You have added some sodium, but no fat, almost no sugar, and almost no additional carbs. The kale is loaded with nutrition, so you are good to go.
Now you can sacrifice your health a little and make your soup more interesting and more filling by adding a pack of cheap Ramen Noodles. Or you can substitute or add mixed frozen vegetables, as well as extra water.  This will make it far tastier, more nutritious, give it a better texture, and go farther.   You decide how much salsa and/or vegetables to add.
Too take it too the next level (as I occasionally do), add a serving of finely diced ham.  WOW !!
And my cost per serving is still only around 16 cents per 1 cup bowl! 1 soup packet makes 6 very hearty cups when the other ingredients are added.
{Soup - .10, Salsa- .27, veggies- .28, ham- .31 and water . . . / 6(cups) = $.16 !!!