The document discusses the concept of opportunity cost. It defines opportunity cost as what is given up when choosing one option over another. It provides examples to illustrate opportunity cost, such as spending money on movies means giving up spending it on candy or saving it. The document also discusses how every choice has an opportunity cost, whether it is a small decision like what to buy for $15 or a larger decision like whether to go to college or not after high school. Finally, it notes that the $320 billion spent on the Iraq War could have instead been spent on priorities like healthcare, education, housing, or reducing the national budget.