well, um hopefully you have everything you need for it & have done research on the care and keeping of ball pythons before you buy the snake...
cage
heat pad (U.T.H - under tank heater)
thermostat to control the heat pad
accurite digital thermometer/hygrometer (not the crappy dialog style round ones from the pet stores)
2 identical, appropriate sized hide boxes (one for the warm side and one for the cool side)
substrate
if you have all the above supplies and have done your homework on the snakes care requirements then your good to go.
in that case, congratz and welcome to the addiction.
oh and when your snake is settled please do take pics and show us what you've got...we here at bp.net LOOOOOVE pictures.