Play games
Choose the game that interests you and play itfor free.
Complete the quests
Every game has some quests for which you will receive Soul Gems.
Receive rewards
You can exchange your Soul Gems for Steam Wallet top-ups, game keys, CS:GO Skins and other rewards.
Roblox has an affiliate program that rewards you with free Robux for every new player that you sign up. You also get a small amount of Robux for every purchase made by one of your referrals. If you're a developer, you get Robux for every new player that signs up from your Roblox Game's landing page.