If the snake looks healthy, if the rest of the snakes they have look healthy and you like it, yes, buy it.
If any of the snakes look thin, have parasites, stuck shed, bubbles at the mouth, gaping the mouth for excessive amounts of time... etc, then pass. If one animal is sick, it's possible that one is too.
But some chain stores have good workers that care for the animals. It's really a individual store, and how it's run.