Almost all pet stores employ staffs that have no clue how to take care of reptiles.
My cages are made by a company called Animal Plastics. They are made out of 1/2" thick PVC sheets. They aren't cheap but a single T8 cage will last a BP (potentially 2 with the divider) their entire lives.
http://www.animalplastics.com
Here is a thread I wrote about them:
http://ball-pythons.net/forums/showt...With-Pictures!