When you change your name, you're taking up extra names. Unless this has changed in the past few years, or my knowledge is spotty, each time you change your name, ROBLOX locks your present and previous names - Meaning that as a user, if you changed your name thrice, you've taken up four names that other users could have used. The cost is there to prevent abuse of the system, such as taking or sniping names. It's also there to act as a cost-based burden, to make you ###### whether you actually want to change your name - If it wasn't there, people would just randomly change their name and then complain about it. So far as the game you're talking about it, for every example that allows it for free, there is more (or the same) amount of games or networks which push a cost onto the user - Certain services, not naming names, push a £10 charge onto consumers to change their name.