Currency in the game is broken down into Crystals and Credits.

Crystals are either purchased from the Shop using real-world currency, or earned via challenges. You can use Crystals to unlock Arena Pass Tiers, obtain new Emotes, Stickers, Victory Poses, and cosmetics.

Visit the Shop in the lower-left corner of the main menu if you wish to purchase more Crystals.

Alternatively, you can simply tap on the plus (+) button for the Crystal located in the upper right-hand corner.

Credits, shown as the gold coin in-game, can be earned by reaching certain Player Levels or completing challenges as a reward. You can use Credits to purchase Arena Pass Boosters, Avatars, Costumes, Stickers, Victory Poses, and Weapon Wraps in the Shop.