Star codes are codes shared by Roblox content creators (e.g. YouTubers) who are members of the Roblox Video Stars Program. These codes can be entered when you purchase Robux. If you use a creator's code, they will receive a bonus 5% of the amount of Robux you purchase. The amount of Robux you receive stays the same, so this is a brilliant way to show support to your favorite "video stars".