Hello and Welcome,
I can only speak from personal experience- do not buy from a pet shop unless the husbandry is correct, the animals look healthy and of good weight, they can verify that the animal was examined by a vet and you have some sort of guarantee. I have purchased from pet shops in the past and lost animals because I was inexperienced and did not realize I was getting a sick animal. I was out not only the cost of the animal, but all the vet bills that went with it.
Since that time I have purchased from Doug Dix at Deerfernfarms. I received a healthy mali female that looked just like the picture I received of her before purchase. While I had some difficulties initially with acclimating, she is now doing great. I would definitely recommend him. He has a guarantee that far exceeds what you will find in most pet shops.
Although I have not personally purchased from Lindsay Pike @ Urotopia (yet), I have heard very good things from those that have gotten animals from him.
I went to the Anaheim Reptile Expo in September, and I did not walk out with any animal. Most of the Uro's I saw did not look healthy. I would be leary of buying at a show unless you come across a reputable breeder that has been recommended on one of these Uro sites.
Bits