Is it "ok" ?
That depends on how you look at it. Its "ok" as in, its not against the law.
Is it morally wrong? Many will say that it is, because it keeps that business going, and its not going well for most of the animals that end up in those stores.
However, others may think that EVERY life counts, and is worth saving. And of course they are. But at what price ? Again, every animal purchased there, means more are coming.
In the end, you have to decide if YOU are comfortable supporting that part of their business.
Just be aware that you may up with a over priced, sickly or mite infested animal. It may have all the issues a "rescue" might have, but you will pay more then if you went to a reputable breeder.
It may go well. It has gone well for many people and no-one should be ashamed of their animal based on where it came from.
Once you actually SEE an animal in really bad shape, it is difficult to turn away. We ARE human. So I just don't go look at them anymore.
Because I have a responsibility to MY animals that are already at my home. Without being able to do the STRICTEST of quarantine (meaning a separate building, no shared ac/heat system) and changing clothes between animals, I just won't risk it anymore.
Sure, there are also risks when buying from a breeder. Esp. if that breeder is sketchy or largely un-known. But the chances of things going south is FAR FAR higher when purchasing at a chain pet store or off of craigslist, as well as "rescuing" a sick snake from some individual.
So basically, its "ok", but not advisable..