DY: I don’t think yogurt is cheaper at all, the probiotics aren’t quantified, let alone certified (that should probably be added to the nutrition facts) and most kids aren’t that crazy over regular non sugar laden yogurt.
I’ve had a doctor recommend yogurt to counter the side-effects of antibiotics.
Plain yogurt is not expensive if you get a 32-oz container.
I admit that CY yogurt is not readily available, at least in my area.
If kids (or adults) find it unpalatable, you can always mix it with fruit, cereal, salad, etc.