Just found an email from my spam folder from PetSmart...The subject is "Welcome to our PetPerks reward program!" but I signed up last year. I have no idea why they just sent me this, but it expires May-28 so enjoy!
I have used it on both me and my girlfriend's accounts, and both worked.
I also used it at my local PetCo, they did take it, but the next day when my girlfriend tried to use it they said they no longer take it, and said it was a decision by cooperate?
You will need the PetPerks membership to use this, it may or may not work for you, so it's YMMV.
Limited to one-time use per PetPerks account.
Offer valid in-store at participating PetSmart locations through 05/28/2018.
Excludes gift cards, charitable donations, and Banfield services.
Here's the link to the coupon.
I have also attached a pdf version to this post.