As mentioned if you don't want to heat your room to 84-85 degrees and keep it there you will want to use a heat pad and thermostat.

Flexwatt = $10 delivered
t-stat = $30 delivered
Tub = under $10
thermometer = $10 - $20
water bowl = $1 to $10 depending on size on place of purchase
Roll of paper towels or free newspaper, I prefer paper towels, brawny to be specific

Ball pythons can do fine in ambient temperatures and no hot spot, but I find they digest better and faster and continue to eat more often.