In 1921, George Halas paid $100 to buy the Decatur Staleys, a founding member of the American Football Association that would soon be renamed the Chicago Bears. Almost a century later, the Carolina Panthers became the latest NFL franchise to sell, going for a league-record $2.275 billion, the first NFL team to top both the $1.5 billion and $2 billion barriers. Here are some previous precedent-setting NFL team sales.