You're generic leopard gecko is rather inexpensive. But some of the more exotic morphs from a breeder will set you back quite a bit. Same with ball pythons, crested geckos, etc. the basic animal is usually less than $50. Red Eared Sliders are very common and cheap, which is bad for them, because people are stupid and put them in fish bowls and other inappropriate living spaces.
The expense isn't usually in the animal itself, either. Proper husbandry is not always cheap. But if people buy an animal for very little, they're often not motivated to care for the animal well. Too small of habitats, improper diet, etc. is a problem for a lot of reptiles. Just the shell problems alone from turtles not given UVB lighting *shudder*
And yea, a lot of American dump them when they get too big or too hard to take care of. A red eared slider that fits in a ten gallon tank is fine. A red eared slider that is 10 inches and needs a huge enclosure to be healthy is inconvenient. Iguanas are cute as babies, not so cute when they're huge, need a big home, and have some pretty wicked claws. Big snakes are also pretty cute when they're tiny, but most people cannot handle a Burmese when it gets large.
