There are very few differences between male and female ball pythons. Aside from the obvious, which is that female ball pythons can lay eggs while male ball pythons cannot, the differences that exist between male and female ball pythons are very minor.
In terms of temperament, both male and female ball pythons are quite docile, and are rarely ever aggressive. The only time a female ball python will show more aggression because she is female is when she is protecting her eggs before they hatch into baby ball pythons. Yet this behaviour is quite understandable.
One difference between the two genders is that female ball pythons, on average, physically grow to be larger than male ball pythons. While male ball pythons will often grow to be 3-4 feet in length, female ball pythons will often grow to be 4-5 feet.
In terms of the initial cost of buying the pet, female ball pythons are usually more expensive than males.
This is because those who like to breed ball pythons prefer to have more females than males, since many females can breed and carry the offspring for a single male at the same time. This makes the female more valuable because the more female ball pythons one has, the more offspring can be produced, while technically, only one male ball python is needed (or at least only one of the certain type of morph necessary to breed the offspring morph).