I think if you really want the best bang for your buck you should consider expanding your budget just slightly up to $135.

This gives you the ability to pick up a Helix or a HerpStat from spider robotics. I haven't tried the full range of thermostats, but in my experience these two are the best. They are also pretty hard to break unless you overload them with wattage. I doubt that is going to be an issue for you.

I hope this is helpful!

Justin