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.
You can exchange your Soul Gems for Steam Wallet top-ups, game keys, CS:GO Skins and other rewards.
Is it worth buying prime, or just playing alot so you can get to rank 21? I think it's worth it to buy prime because then you have a higher chance of not to playing with hackers. Of course there will be some hackers, but not as many as there would be without prime. I currently do not have prime but I'm trying to save some Soul Gems and get a Steam Wallet/giftcard. I have thought alot about it and I don't know if I should grind for rank 21 or buy it. Have you bought prime, and do you think it is worth it?