More about this coupon script / WordPress coupon theme here: http://buildyourwebsite.info/coupon-script
This is the tutorial of one of the most powerful WordPress coupon theme which is comes with all the necessary functions you will need to create coupon site.
As you can see this coupon script allows to import huge number of discount codes easily. This way you can make a coupon website with a lot of coupons easily.
You can check out the admin panel demo here of this coupon theme: http://www.youtube.com/watch?v=yU31Q6bBNxs
Here is another very powerful coupon script which has similar options: http://www.youtube.com/watch?v=32Mu5srqNv0
Overall, if you want to create a coupon site, you should check these coupon site scripts.