Yes, it’s possible to use Microsoft Rewards for Robux. This allows users to earn points by completing simple tasks, like using Bing, shopping at the Microsoft Store, or taking part in daily quizzes.

To obtain the 100 Robux digital code, you must now earn 1500 Microsoft Points. It's fairly simple to obtain the 1500 points because all you have to do is use Bing for 5 days.