Don't buy from the pet store. Redshepherd did a pretty good job explaining why... they tend to be disgustingly overpriced and more than most beginners can or want to handle, what with the likelihood of mites and other health issues hitching a ride home with the new critter.
Try attending your locale's next reptile expo. Most places have some within reasonable driving distance, they occur multiple times a year, you get a huge selection of animals you can examine in person and who's breeders you can talk to if you have questions, and I'm sure your kids would probably think it's a blast. Plus prices tend to be more than fair at the expos, and you don't have to pay shipping. They also have tons of reptile related supplies too if you need to stock up, and always for cheaper than any pet store.