If you've added a Facebook advertising coupon to your ad account, you can see information about it in your payment settings:

Here, you can check how much money is left on your coupon, when it expires and its original value. The value of each coupon varies and is stated when you receive one.

Bear in mind that coupons will be charged first for advertising costs that you accrue after one has been added to your account. However, a coupon can't be used towards any costs you accrued before activating your coupon. Those costs, as well as costs that you accrue once your coupon has been used up, will be charged to the primary payment method of your ad account or your prepaid balance (if you use a manual payment method).

Learn more about how you're charged for ads when using an advertising coupon.

* Nguồn: Facebook