The "Clown" morph is a recessive gene trait - I really couldn't tell you the current prices because I haven't looked at purchasing one in a long time, but if you search the classifieds here and elsewhere you should be able to get a decent "feel" for the average costs. Plus (since I don't know how well versed you are in genetics) you'll have to consider whether you are looking to purchase a heterzygous pair and produce a Clown yourself (cheapest and most time consuming route) or if you are going to go for gold right out of the gate and purchase a homozygous (visual) Clown (or pair of Clowns).
If you have prior experience with other species, caring for a ball python shouldn't be too big of deal for you (the biggest hurdle for you will be dealing with their feeding habits), but I would still recommend purchasing a normal or two (or one of the more inexpensive morphs) to help get you into the swing of things. That way, if you screw up and the worst happens (ie: it dies) you won't be taking too big of a financial loss. Try caring for one or two hatchlings until they are a couple years old so that you'll be sure to get the hang of dealing with their seasonal fasting periods and will learn not to stress too much about their dietary intake.
As far as their care requirements are concerned: every ball python has the same general care requirements no matter the morph. The only thing different between the cheapest Wild Type and the most expensive combo morph (besides for the price tag) is their paint job.
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Stay United!

I'm still not sure if it's weird that my best friend is a two year old boa named Ronin. He's quiet, non-judgemental and listens... what more could you want?