Best bedding

[Oxylepy]

Deborah covered it best.

There are a few groups of substrate that are best, it depends on your situation.

Dehydrating Bedding
Someone recently purchased and used Reptile Litter, which is super dehydrated nuggets of aspen. This is Litter style bedding, highly absorbant and dry. Even in a very very humid environment, this isn't really advisable for Ball Pythons, you would want a dehumidifier if your humidity is that high.

Dry Bedding
This is bedding which doesn't increase the humidity, but it also doesn't tend to dry the area out much. Aspen and newsprint fall into this category. They tend to not be moist when introduced and tend to stay that way. (I've poured water on my aspen before, it can take minutes to be absorbed). These are good beddings for situations where you don't need to increase ambient humidity more than just the amount your water dish will increase humidity.

Moist Beddings
Mosses, coconut, orchid bark, coconut husk. These beddings are ideal for holding humidity, and maintaining a higher humidity in the enclosure. Perfect for dry rooms, open top enclosures... Essentially this is the bedding for when your dry beddings plus your water dish aren't cutting it.

My suggestion for anyone setting up an enclosure is to start with aspen. From there, reduce the humidity loss in the enclosure (covering screen lids in screen topped enclosures, upgrading water dish to a reasonable size) until you have exhausted the primary sources of humidity loss. If your humidity is still low, then upgrade to a higher humidity bedding. It will save money, serious effort, and stress for you if you do it this way.