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.
Save 100% on Go! Go! Nippon! My First Trip to Japan
https://store.steampowered.com/app/251870/Go_Go_Nippon_My_First_Trip_to_Japan/
1) sign in to your steam account
2) get the game and keep it forever !
I'll be making free games alerts like that from now on !