The Coupon System consists of virtual coupons that can be used to purchase Cosmetic Items at a discounted price. Certain purchases will trigger a bonus coupon for users which they can immediately redeem to gain a discount or bonus on their next purchase. Unused coupons can be seen in the Rewards Center.
For example, any users who buy the Infiltrator Loki skin and do not own his voice pack, will receive a 50% discount for the Voice Pack if they choose to redeem it.
Coupons are only rewarded for things set up and flat (no automation), and Coupons have an internal cooldown so they won't happen back to back.