It seems you already have a ball.
Well, the pastels are the cheaper of the morphs so they are a bit easier to buy, I'm looking into buying a pastel myself this upcoming season.. I also want to look at spiders though. (The money can kill me.)

Buy one from a good breeder that has a very good reputation and such. You don't want to come home with bad genes and mites. ;]

What exactly is in your budget?
Also, if you plan on breeding your python, look into males?
Are you going to house them together? If so you have to quarantine him in a separate bin until it's guaranteed healthy or proper size.