[ringleader]

Originally Posted by ChurchMedia

2) It would be ideal to be able to assign more than one subscription ID to a coupon. You could code this pretty easily using "explode" for commas.

It was simply because I would have no use for that that I didn't think of it before
I'll add it in this weekend to the new, hopefully much cleaner, version.

Originally Posted by ChurchMedia

3) When you assign a coupon code, the code is changed to lower case ($coupon_name = strtolower($coupon_name). That isn't good for me because I'd like to use all-caps in my codes. I can just comment out the line, but you might want to make it optional or something.

Pure laziness made me do that!
The check when the person inputs a coupon in their payments.php (in any case, upper or lower) will convert it to lower and check it against the lowercase version in the DB. It's just easier for all. The reasoning was that people don't notice case-sensitivity when inputting stuff like this.
So you can use upper or lowercase for your coupons - it's independent.