Everything we need and want in our lives costs energy in the form of money, time, or both. In this lesson, Young Professionals (YPs) consider the things humans really need to survive—to stay alive. Then, they examine the things they want, their reasons for wanting them, and the energy costs of obtaining them—in terms of both time and money. They consider the cost of a toy in terms of how long it would take an adult to work to earn the money for that toy at different hourly rates of pay.