Hello, andto BP.net. The difference in the prices that you are seeing is due to the different genetic morphs of the color and patterns. You can get normal patterned Ball Pythons for as little as $30-$40 at a show. When you start getting into the different morphs, basically the more rare or complex the genetic soup is, the higher the price. Depending on the morph, they can cost anywhere from a couple hundred dollars to tens of thousands of dollars. But even the "Normals" come in a wide variety of pattern variations.
Here are a couple threads with alot of photos of normals, to show their variety...
http://ball-pythons.net/forums/showt...-beauties!-DUW
http://ball-pythons.net/forums/showt...-are-Beautiful!
As for your cats, I would suggest just keeping them in another room when handling the snake, then you won't have to worry about any potential accidents between them...