Never EVER EVER use Cedar. The oils in it are deadly to snakes. And while you can totally get away with using a fish tank for a home, it is recommended to use a tub or even a PVC tank. Sure, they'll cost more, but they're easier to maintain humidity in. Or you can make your own with plexiglass like I've seen around on the internet before. Some people do great with just a plain Rubbermaid storage bin for their BP's. (With proper air vent holes and heaters and such, of course! )

But, yeah, totally listen to these guys above me. They're great and I learned a lot by roaming the forums and reading their posts. Balls are wonderful pets. I loved mine dearly.

Here's a site that sells PVC cages and accessories that you can get for pretty good price. http://www.pvccages.com/new/
I was thinking of getting one from there before Penny passed away.