What is the typical cost to have a ball python for pet?

I'm not sure on the costs of the tank and such, because I used an old fishtank/aquarium that I had lying around.
I use heavy brown paper (the kind that comes in big rolls) for an easy-to-clean and cheap surface. Buy a couple heat pads, a full-spectrum aquarium bulb for reptiles (maybe around 20-30) and you should be set. Find some rocks outside, clean them off and you're good.
Get a structure for the snake to hide/coil in, and a water dish.
As for food, if you can train it to eat frozen/thawed rodents, you can mail order them online for a bulk discount. I'm not sure what the price is per batch; I haven't bought any in a year since she doesn't eat very often.
Also, it is recommended you get another enclosure for feeding, so the snake won't associate the tank being opened up as feed time, in case you just need to hold it or clean the tank.

I'll try to find my rat cost, but it's not that bad once you buy all the equipment.