a. Money spent on a new car could of been put in saving or used for food, clothing, vacation expenses, education expenses etc.
b. When deciding how much money to allocate towards national parks, members of Congress much calculate the trade-off with other important expenses such as national defense, infrastructure (bridges and roads), social programs, education etc.
c. Opening a new factory may limit investments in other projects, operation expenses, capital on hand etc.
d. Trade-offs a professor should consider when deciding how much to prepare for a class include time spent with family, personal activities and research.
e. A recent college graduate that goes to graduate school would trade-off earning money now with a full time job and the money it costs to go to graduate school.