Price signals can take various forms, including changes in the price of a good or service, changes in taxes or subsidies, and the use of market-based mechanisms such as cap-and-trade systems. By altering the price of a good or service, governments and other organizations can influence the demand for the good or service and the quantity that is produced. For example, if the price of petrol increases, consumers may be encouraged to drive less and to consider alternatives such as public transportation or electric vehicles.