I would not buy a reptile from a large corporate chain with poor reputation in reptile care. There are far too many alternative sources to buy a ball python from.
Heck, I obtained 2 of my beauties on cragislist! Just make sure to check the animal carefully for signs of disease. A lot of people buy ball pythons and quickly get tired of the novelty and try to rehome them in classified ads. If you want to get a good deal, you can check out your local classifieds. If there are any smaller, more specialized reptile shops nearby, you could check them out also. There are petsmarts and petcos all over the place around here, but there is an Aquarium and Imports store that only carries fish, reptiles, birds and small mammals. Privately owned, and I always check out their reptiles. They have reticulated pythons and a lot of cool animals that you cannot find at PetCorporateMart.
If you do not want to pay for shipping, you could wait until a reptile show comes nearby and buy from a breeder directly.