Animal pricing, especially in chameleons is usually due to genetics.
The higher quality the animal, the more expensive it will cost. Purchasing from a breeder is usually less expensive because the breeder pockets the money. Purchasing from a pet store costs a lot more because they owe money to the breeder, but at the same time must make a profit.
Usually pet stores buy low quality animals, they are not really looking to sell to experienced keepers. This also means they pay less for the animal and thus make more profit. To top it off the animal is usually in squalid conditions - chameleons especially.
It is very sad to walk into the store and see some animal that looks abused and lonely, and the gut feeling to do the proper thing and buy it usually sets in. But just remember if you want such an animal, buying direct from a high quality breeder will give you a better animal at a lower cost. Not purchasing from the pet store also sends the message that you will not support their practices. We all know that if you bought their chameleon it is just incentive to stock more chameleons and they too will be kept in those same squalid conditions.
While it is a very sad story for that one, not purchasing him prevents the same treatment for many others.
S.F