For a "Can-o-'mater" soup - I generally use 1/2 can of milk and 1-Tablespoon of butter + a pinch of black pepper. Some saltine or oyster crackers are always a nice "garnish".
To "gussy" it up a bit ... and make it something totally different ... leftover white rice, some "meat" (diced chicken, kielbasa or shrimp), scallions, okra ... etc.
Po-Boy (Dorm Daze - College Days) Tomato soup (requires some scavenging):
12+ condiment packets of tomato catchup, 1 packet salt, 1-2 packets black pepper, 2-3 packets of saltine crackers (3-4 per pkg). Instructions:
1) Turn on hot water tap to get it as hot as possible
2) Into a 1+ cup bowl empty the catchup packets (the more the thicker the soup will be)
3) Add salt and pepper packets to taste
4) Slowly add water while stirring .... about 1 cup (or more depending on how many crackers you have)
5) Crush crackers and add
If the catchup is really lame/bland - add 1 pkg mustard.
If you are entertaining a date - double the recipe and get a 2nd bottle of Boone's Farm. If you are a child of the '60's - and probably smoking something that is not legal - triple the recipe and get 2 more bottles of Boone's Farm (2 Apple and 2 Strawberry).