A coupon code is good for each ad. So if you have 5 ads to place, you must use the coupon each time you place an ad.
Some coupons have a limited use feature. So if the coupon is only good for 100 times, then it might not work on all of your depending on how many time everyone with that coupon code has used it.
← Do the coupon codes give me unlimited free ads for the time period?