Roblox allows all users to change their Roblox account's display name in the account settings without spending a dime. Here's how to do it.

Change Roblox username or Roblox display name When you initially sign up to play Roblox, you must give your Roblox account a Roblox username. Other players will see your Roblox name in game.

To get or change a Roblox Display Name, you should first log in to your Account Info page under Settings, then select the edit button next to the Display Name entry above your Username.