I agree with Mr.Misha, buying from a big store is simply supporting them and their ways of animal care. If the animal sells expect another one in the same conditions next week.
Some times you can find people on craigslist trying to get rid of a snake that they bought on impulse and only look at it once a month to throw it a rat. If you can rehome it and give it a caring home with proper husbandry go for it.