I don't know... I might get bashed for this, but I feel like I have to say something. If you can't afford something as little as another tank for your snake, let alone a much needed thermostat, that you have to pawn your own "engagement" ring.. Maybe you should think about rehoming your snakes to someone who can afford these things so your snakes don't get hurt. Then, maybe, once you get a job and some money, get a setup completely ready before hand, and look into adopting another snake.
Just my $0.02....