You shouldn't grow at your parent's house, it's as simple as that. Well, without them knowing, that is. I mean, if you get caught growing in THEIR house, they're going to get shit from it, not you. I mean, would you want that from one of your kids? If you're set on growing, just talk to them about it. Present information, inform them how it would be easier and safer if you grew it yourself. I mean, you're not exchanging with drug dealers and you know that it's not contaminated, cause you grow it yourself, right?

With that said, there are many items which will cater to your needs. Fake computer towers might be perfect, however, I'm not sure that fits in your budget. Good luck and so forth.