so, I had a little minor battle with sallly's...
I had already purchased curlformers. When I bought them, I asked the cashier about the return policy. She told me that as long as I had the original packaging, I could return the item. So...
After I saw the coupon, I decided to get a price adjustment. Meaning, rather than return the item, "return" the item then buy the item right back with 15% off. Initially, the cashier was adamant that it could not be done. She said they do not do price adjustments and I could not return the item. So....
I asked for the return police in writing. She couldn't produce it but insisted that she was correct. (politely) I asked for the customer service number.
When I returned to my car, I called the customer service number. Within minutes, the customer service rep stated that the cashier would give me my refund and I had no difficulty getting the price adjustment I wanted. I returned to the store and saved $12 on my curlformers (that's like getting one pack for free).
I hope this information helps someone in the future. Thanks to the OP for saving me some bucks!