There are two methods to get free robux
1st method: microsoft rewards
1: enter bing browser (gives you more points unlike the other browsers
2: while in bing search for microsoft rewards
3: go to earn and complete the challanges and all that
4: when you get a certain ammount of points go to redeem and scroll until it shows robux gift card
5: redemm the gift card (as long as you have the points needed in which you should get a code)
6: redeem the code and you should get the robux (for free)