Hard to say here too. All my Leos were rescues. Even though they all came with caging, they needed MAJOR changes. Three of the rescues came from a smoking house and everything in there REEKED of Cigarettes. I wasn't able to save anything except the tanks, and one of them was cracked. I find it's the heat pads and lamp fixtures that really cost ya. Substrates too. I got suckered into sand at fist, that can be 20 dollars just to cover a 10 gallon. I use ceramic tile now, 6 dollars and lasts forever. I scrimp where I can, I breed my own mealies so feeders don't really dent my wallet. Although the gutload for them and the calcium supplements can add up. It's really hard to give a good estimate. But for a 20 gallon tank and all the stuff to set it up, last time I did that, cost me a little over 100 dollars.
My snake was $70 bucks (rosy boa) which is a steal considering I got him from a herp specialty store. However I think I got what I paid for because he was a biter at first and I've found him to be a problem feeder also.