The purpose of the Monopoly "Get Out of Jail Free" card is to provide players with a means to avoid the penalties and restrictions associated with being in jail. In the standard rules of monopoly go unlimited dice, when a player lands on the "Go to Jail" space, draws a "Go to Jail" card, or rolls doubles three times in a row, they are sent to jail and their token is placed in the jail space on the board.
While in jail, a player's options are limited. They cannot collect rent or purchase properties. However, if a player possesses a "Get Out of Jail Free" card, they can use it to immediately leave jail without having to wait for a specific number of turns or pay a fine. It grants them the freedom to continue moving around the board and engaging in regular gameplay.
The "Get Out of Jail Free" card is considered a valuable asset in the game, as it provides players with increased flexibility and a strategic advantage. It can be used by the player who owns it or traded with other players as part of negotiation and deal-making during the game.