I’d never knock people who bought pets from breeders (pet stores are another story), but anyone who’s adopted an animal from a shelter, I think, develops a softer spot for homeless animals.
The Animal Rescue Site has a current promotion whereby visitor clicks will elicit sponsors to donate funds to the care of shelter animals. Snopes confirms it’s legit, so bookmark it and click away.
And, like Bob Barker says, get your pets spade and neutered. Dammit.