Hi David,
Here are some discount codes that I have been using for a while. They have always worked great.
Petco.com: The coupon Code "
Report10" gets you 10% off any purchase
The coupon Code "
Report" gets you 10% off + Free shipping on purchases over $65. You can place these codes in the check out area at petco.com
1800petmeds.com: Type in your url browser. "
1800petmeds.com/hop" and that will activate a 10% discount. You will see the discount take effect when you view your shopping cart.
Cheers