The modern day Dollar Stretcher e-publication had a story in it I concept is probably appealing to parents who study this weblog:
This struck me as an incredibly useful exercise. It would be especially handy for home-schoolers, who can use it to combine a math lesson with a life lesson, but really, I think all parents could make use of it. I suspect that many American adults have never really learned to grasp the concept of opportunity costs (i.e., "doing x means you have less money for y"), and would be much better off if they'd been exposed to the idea while they were young and impressionable. Parents who teach their kids this lesson would be doing them a lifelong favor—and they would benefit themselves in the short term, as their kids might stop pestering them for goodies that don't fit into the budget. (Or at least, if they do, they'll have to accept the logic of the answer, "Buying you a new toy will leave us less money for food, remember?")