I had half a container of tomatoes left from the previous night's dinner. I added that (about a cup) to a bowl. Then I added about 1/2 cup milk (you could use half & half if you have it and it would be SO YUMMERS!) I also added a tablespoon of simple syrup, and then a pat of butter. Oh, salt and pepper of course.
Microwave it until hot, which was 3 minutes at my house. Rich, hearty, cheap, fast and delicious. This makes a chunky tomato soup, but you could blend it first for a smooth soup. If you want it thick, you could add 1/4 teaspoon corn starch before microwaving it.