Gorgeous pattern on that guy! And like Christie said, it's hard to tell how big he is with those pictures, but I would guess a juvenile. Just guessing, though.
As for another snake, corn snakes are great. They come in a LOT of different colors (morphs) and that is why you see such a wide swing in prices...kind of depends on how common or rare that particular morph is. You can always find affordable cornsnakes though. And they're very easy to take care of.
If you're looking for something your niece can hold, keep in mind that a baby or young corn can be highly agitated and flighty. Not at all suitable for very young hands. This is true for most any baby snake I can think of. Your best bet with a youngster is to hold the snake yourself and let her pet it, which you can do just fine with the BP, too.