Really, one of the biggest no-brainers out there is that your local shelter is the best place to find your new companion animal. Granted, some of them aren't the nicest places to visit, but it only takes a couple of hours to go through the adoption process. Maybe you need to visit several times, but it's worth it, isn't it?
Imagine if you were one of those animals that lived there, either until adopted or until euthanized. Remember that these places aren't always well-funded, and the staff is 99 times out of 100 times overworked, underpaid and underappreciated.
Each year millions and millions of healthy, adoptable animals are senselessly euthanized because of the lack of homes for them all. Most breeders and all pet stores (that sell puppies/kittens) care little about the animals they churn out of their establishments. It's all about the money.
For a long time, the purchase of a puppy or kitten could be chalked up to ignorance, not knowing what goes on in the puppy/kitten business. Maybe folks don't know where their local shelter/ASPCA/breed rescue is. Below are some links to the local groups. These will be updated from time to time.
Now that you have the information and the education, go find your new companion. No more excuses for buying a best friend. Knowing what you know, from this day, if you buy while homeless die, you might consider working on your morals.