$30 Credits for Pet Products at petco.com for $20

Everything Petco does stems from its mission to make the world full of happier, healthier pets. That's been the goal since Walter Evans founded the company in San Diego in 1965, back when dogs couldn't even legally become homeowners. Originally, Evans's company went by the name of UPCO, and it provided mail-order veterinary supplies. It officially became Petco in 1979, announcing the name change by entering a giant cat float into El Cajon's Mother Goose Parade (it won best float).

Petco has made communities around the continent purr ever since. Each of the more than 1,400 locations in the 50 states, Mexico, and Puerto Rico is stocked with pet toys, food, and vitamins. The stores also carry a vast array of other supplies for all sorts of pets, from dogs and cats to fish, ferrets, rabbits, and birds. Many of the stores even provide essential pet-care services, such as grooming, training, and vaccinations.

But perhaps no service is more important than Petco's Think Adoption First program, which has found forever homes for millions of pets over the years.