The short answer is a very simple "I wouldn't".

You can very easily find a reputable breeder and have the animal shipped for about the same money and often less than buying from the big box stores.

The big box stores are often overpriced in the first place. Combine that with a MUCH higher risk of mites, etc...and a vet bill and you're already in for more than you would have paid for a quality, healthy animal from a reputable breeder.

I, myself have actually spoken with management on many occasions at my local big box stores as well as called corporate on two occasions. Not worth buying an animal from there.

Somebody above mentioned that buying from there is basically getting a "rescue" animal, which in some ways is accurate, but consider this: a rescued animal is taken out of a bad situation where proper health, husbandry, etc... are not provided. Buying from the big box stores may take one animal out of one enclosure, but only at a HUGE profit for the store and that enclosure will be filled within days with another mistreated animal.
Check out Aerries post above, that should answer your question....

Anyway, morphmarket is probably your best bet. There are also some great breeders right here on this forum. Maybe start a new thread saying you're looking for a certain morph and ask if anybody has what you're looking for.