Of all the recent attempts to explain capitalist economics in terms of pint-sized business ventures, this is the most personable. Amy's need for a hundred dollars for a camping trip starts her thinking; considerations of expenses, demand, and profit lead her to reject several possible products; and after she settles on terrariums (as the pet store is selling fishbowls at cost), she starts calculating costs and losses, discovers that her time is worth money, and learns about interest and how banks can pay it. A small setback necessitates ""floating a loan"" (borrowing from her mother) for the camping trip, and later she raises more capital by getting her brother and a friend to invest in the business--but competition, inflation, and uncertain demand finally decide her to close down while still ahead. Still, it's a happy ending, with all three kids bubbling with ideas for their next venture. Unlike most such undertakings, this is neither a string of definitions, an overambitious macro-survey, nor a plug for the system. It could start readers growing their own profits.