Elon Musk's X platform is set to launch the "X Handle Marketplace," enabling Premium Plus and Premium Business users to trade unused usernames. The marketplace categorizes usernames into Priority, which are free, and Rare, which are paid and can range from $2,500 to over a million dollars based on demand and uniqueness. Once a username is changed, the previous one is frozen, and downgrading a subscription will revert the account to its original username. A paid redirection feature is also being considered for future implementation.