Petsmart is offering 25%, 20%, 15% Off Single item through there Treat Trail game in their app. Download the app in the app store and at the bottom you will see Treat Trail.
Theres the link to my original post with screenshot. I've attached a recent persons purchase of a Fluval FX6. Also from the original post, some people were able to get petsmart to stack all 3 coupons on a purchase. Good Luck!
The games kind of hard...just make sure on the 25% hard level, you try to save up your stacks and it shouldn't take you longer than 30 minutes.
Petsmart Mobile App