In a market economy, suppliers produce goods and services and set prices based on what consumers are willing to pay. Prices respond to consumer demand, and transactions occur voluntarily when both parties benefit. A supply curve graphs the quantity suppliers will provide at different prices, while a demand curve shows what quantity consumers will buy. When graphed together, they determine the equilibrium price where supply and demand intersect. Competition between suppliers drives prices down and innovation up, while competition among consumers pushes prices up. Profit is an incentive for entrepreneurs to take business risks. International trade involves exporting goods and services to foreign consumers or importing them from abroad. Governments regulate trade with barriers like tariffs and quotas. Different currencies are used in various countries.