Here's a recipe I found online to use instead of cream of whatever soup in recipes (not sure if it's any cheaper, but it's healthier):
4 T butter
4 T whole wheat flour
1 c broth
1/3 c milk
In small saucepan melt butter over med heat. Add flour and stir till bubbly. Slowly add broth and milk, stirring constantly. Cook till thickened.
This is the equivalent of one can of cream of xxxx soup.
I don't know how this would work as a soup, but this was easy to do, and worked well to replace a can of cream of chicken soup in a recipe I made this weekend.