Trade is the transfer of ownership of goods and services from one person or entity to another by getting something in exchange from the buyer. Trade is sometimes loosely called commerce or financial transaction or barter. A network that allows trade is called a market. The original form of trade was barter, the direct exchange of goods and services. Later one side of the barter were the metals, precious metals (poles, coins), bill, paper money. Modern traders instead generally negotiate through a medium of exchange, such as money. As a result, buying can be separated from selling, or earning. The invention of money (and later credit, paper money and non-physical money) greatly simplified and promoted trade. Trade between two traders is called bilateral trade, while trade between more than two traders is called multilateral trade.

Trade exists for man due to specialization and division of labor, most people concentrate on a small aspect of production, trading for other products. Trade exists between regions because different regions have a comparative advantage in the production of some tradable commodity, or because different regions' size allows for the benefits of mass production. As such, trade at market prices between locations benefits both locations.

Rudy Carlton Gay, Jr. (born August 17, 1986) is an American professional basketball player who plays for the Memphis Grizzlies of the National Basketball Association (NBA). He played collegiately at the University of Connecticut before turning pro.

Gay was one of five siblings and began playing competitive recreational basketball at 12 years old in the Turner Station community of Baltimore County, Maryland in one of the toughest youth basketball leagues in the area. Early exposure to Baltimore AAU basketball and summer league games in the Tom Jones Youth Summer League in Washington, D.C., showcased his abilities against top competition.^{[citation needed]}

At the age of 14, Gay began playing for the nationally-known Cecil-Kirk AAU program under Coach Anthony Lewis with other blue-chip players such as Josh Boone (UConn), Paris Carter (New Mexico State), and Chester Frazier (Illinois). During the spring of his 8th grade year, Gay and teammate Scott Dozier were highly sought after by several private schools. Gay attended Eastern Technical High School in Baltimore County, while Dozier enrolled at the St. Paul's School.^{[citation needed]} Gay transferred to Archbishop Spalding High School of the Baltimore Catholic League after his sophomore year at Eastern Tech.^{[citation needed]}