Tarisland is a free-to-play MMO with many different currencies, both free and premium. One of these currencies is the Stone of Prayer, which you can spend on the Reward of Destiny.
The Reward of Destiny is a gacha system in Tarisland, and the Stone of Prayer is the “pull” you can spend for a chance to get limited-time cosmetics. If you played gacha games, like Genshin Impact, this mechanic should be very familiar to you.