If you have a UTH (under tank heater), you NEED a thermostat. From what I know (which isn't very much) most UTHs get up to about 130+. Mine did, and I wouldn't get a cheap thermostat. You need to spend the money here if you skimp out on everything else.

Herpstat is great! I've heard helix's are good as well as ranco. I think people use rancos more for racks and incubators.. correct me if I'm wrong..

Welcome to the ball python world.