I buy a large can of black beans for $2.30 and about $4 of pork from a local latino market. I get an onion for around .20 cents.
I cook the beans and mix it with rice ($3.70 a package---using about 2-3 cups dry rice). This makes a meal that can feed a person with a healthy appetite at least 5 servings...which equals
$7.50 total (estimated eating $1.00 worth of the rice, probably less than that) with $1.50 spent per serving.
I like to try and make servings be under $1.00 whenever possible.
Except for when I go out to eat, then it is a moot point.
