Unfortunately, the world isn't kind to most animals, and a lot of chain pet stores keep them in awful conditions, where they are parasite ridden, vitamin deficient, and slowly dying of preventable diseases. These animals are sold as pets, usually to inexperienced owners who don't know what they're contributing to.
When you buy from a shop, you pay for everything that went into the product. For instance, if you buy a shoe you're paying for the leather, the cotton, the dye, the plastic, the manufacturing and labor costs, the transportation costs, and, of course, a little on the top so the store makes a profit. This isn't even going to the costs of raising the cotton plants and the cows that go into the very early stages of manufacturing.
It is the same when you buy a leopard gecko. The breeder paid for the supplements for the gravid mother, the electricity to run the incubator, the supplements, food, and heat for the hatchling, and the shipping costs to send the hatchling to the store. Of course, many of the suppliers for the larger chains, such a Petsmart and Pets at Home, use reptile mills. For more information on that, just Google "reptile mill Petsmart".
I would guess that they price the geckos up approximately 25 - 50%, so if Petsmart buys a leopard gecko for £20 from a breeder, they then charge £25 - £30 to the consumer.
At the end of the quarter, the manager will send a report of sales to corporate. Corporate don't think of the animals they sell as living creatures - they are simply stock. They look at the bland spreadsheet that's been emailed to them, and they see that the pet store sold 346 leopard geckos. They see that that's more than any others in the area, so they order 400 leopard geckos in for that store to sell in the next quarter. They don't buy more cages for the leopard geckos, because that would reduce the profits for the next quarter.
They don't purchase any extra time with the vet, nor any more medication, since the sickly geckos got purchased by well-meaning rescuers too, and therefore the "product mortality rate" percentage was fairly low.
This is the problem. In order for Petsmart and Pets at Home and all of the other giant pet suppliers to stop neglecting animals, and to stop abusing the lousy animal rights laws, you have to change that spreadsheet. If the spreadsheet said they told 22 geckos and had a mortality rate for 78%, they would stop stocking them, and the breeder who runs the reptile mill would go out of business.
So, what can you do?
If you see a sick animal, and you have the funds to care for it, then ask to speak to the manager.
Get either a huge discount or the animal for free. You don't want them making ANY profit on this sale. Before the animal is removed, take photos of it and it's setup.
Send the photos to your local politician, as well as animal rescue groups backed by the government.
If you don't have the means to care for a sick animal, then report it to the authorities as animal abuse or neglect.
DO NOT PAY FULL PRICE FOR THE ANIMAL. They will want you to, but if you do, three more animals will take its place.
I hope that this post helps people have a better idea of the long term consequences of purchasing, and gives owners a better understanding as to how companies like Petsmart and Petco function.