The tarantula hobby has grown over the last couple of decades to the dimensions I thought I'd never experience. Because this is not something people did 30, 40 years ago for sure.
Tarantula hobby is big at the moment. And there are a lot of extremely knowledgeable people out there. The first line is, ironically, reptile shops. You'll find stores that are specializing in reptiles. Naturally they go to amphibians like frogs, newts, toads and salamanders. And further naturally they go to invertebrates. Millipedes, scorpions, tarantulas, centipedes and the like are all becoming common captive bread animals.
So for the common person that's the usual place to go. Is an animal specialty store, an exotic animal store or a reptile store. Check out listings in your local papers. See who's around where you live. If you're not in an area of the country that has a shop like that, sorry. But then online is the only other place to go.
And I would look for the many excellent tarantula breeders who are on the market right now. People who work usually from a home based business, but just have an arachnophobia that's a good kind. And that they love tarantulas, know more about them than most scientific people and will steer you in the right direction. Responsible purchasing comes from responsible sellers. And that's what you have to seek out. People who are not just looking to make a quick sale and tell you anything you want to hear. That tends to be more in the big box store type of pet stores that have dogs, cats, fish, birds, oh yeah we have tarantula. They can't possibly be as knowledgeable as somebody who breeds tarantulas for a living.
So stick to people who really know their stuff, the local specialty shop or the online breeders. Breeders are fantastic, of course, because you're getting captive breed animals, not wild caught ones.
So do your homework on who you're purchasing from. Just as much as you're doing homework on what you're purchasing. And you'll have an excellent experience having a tarantula as a pet.