This month Petmeds are offering a few discount codes instead of just one:
PetFoodOffer - Gives 7% discount on all pet food
PetDisc5 - Gives 5% off everything
PetDisc10 - Gives £10 off when spending over £100
Feliway10 - Gives 10% off feliway products
These codes are valid until the 21st May.