Piebalds run $5,000 and up right now depending on how much white is on them.

If you can get to a reptile show that would be the best option, as you can get truly captive bred ones there. A lot of suppliers that sell to pet stores take "farm-raised" animals and label them "captive bred", since technically they weren't bred out in the wild, but they still have a lot of the same problems a W/C animal does.

The biggest problem with Ball Pythons is that they tend to go on fasts. This isn't really a problem per se, but it does stress out a lot of first time snake owners. I recommend keeping a record of the snake's weight at each feeding, and if he fasts, remember that as long as he's not losing a lot of weight it's not a reason to stress out.

Pre-killed is IMO the best way to go, and most BP's started young have no trouble switching to pre-killed. If the snake is reluctant to eat at first, starting it on hamsters or preferably gerbils instead of mice, or scenting the mice on a hamster or gerbil will usually do the trick.

I've never had a BP, this is just my experience from working in a pet store and a reptile store and with a few friends who raise/breed them. ILoveReptiles can probably give you more detailed answers.