A large dose of creativity and talent will be part of the attributes you will need if you want to work for Roblox as one of the methods to get free robux legally, being this, an aspect that will be conditioned by your experience and trajectory as a player within the platform where you can have the opportunity to choose some of these options:
Sell your creations at the Builders Club
If you are a person with skills in designing Roblox items such as wings, hats, pants, shirts, among others, you can take advantage of this to put all these creations on sale in the Builders Club market along with the rest of the items you have acquired from other users, this being a way in which you can obtain robux legally and quickly.
In addition, you can enter the Group Recruitment Center section in case you have the ability to develop scripts for Roblox games, making this service available to any user who requires it.
If you are a prodigy in terms of building structures let me tell you that this can give you a great chance to get up to 2000 robux in case you are hired by another user who requires this service.
Develop a popular game in Roblox
Working as a game developer for Roblox is another way you can put your skills into practice and get robux legally with it.
This way, if you have the technical skills and creativity to attract the interest of a considerable number of players you can have the opportunity to get, through the sale of Game Passes, a commission of 10% if you are not registered as a member of the Builders Club and 70% if you are, which you can then exchange for robux.