Thank you all for your answers, they are all very helpful!

My parents have me pay for all of my gerbil stuff myself, so that's why I said I would want to get a tub. However, I didn't realize that I could probably make a deal with my parents and pay them back overtime for a PVC enclosure . From my research, PVC seems to be very insulating, but my rooms tends to be on the cooler side, so I was wondering if the temperature of my room would affect the inside temperature of the enclosure too much? Also, when you use an RHP, where do you put the probe for the thermostat? I don't know what age ball python I would get, but if I got a young one, is it okay to put them in the enclosure they would live in as an adult? I read that they can live in any size as long as there is enough clutter.

I'm glad to hear that my gerbils wouldn't be an issue.