1) Check the coupon code
If you have any cash coupon by hand, please refer to My Account to see whether the coupon code is added or not.
2) Use the Coupon for your Order
When there's any active coupon in your account, it will be shown in the Payment Center, then you can choose the coupon to pay for the order. Just as follows:
Terms & Conditions
If you have any question, please feel free to contact us.