I have some decent $30 thermostats I got a herpsupply.com. I have 4 of them currently and I really love them, and they work well for me because I never had more than 3 reptiles at one. I use one for the hot side, directly over the mat, and I check this area with the temperature gun every day because even mats can develop hotspots. The faulty probe I found probably was probably due to it getting wet at some point on my part. Then, I have another for the cool side. There's probably a more economic way to do things, because $60 for thermostats every time you acquire a new animal probably isn't the best way to go LOL. It also gets confusing sometimes when you're trying to find out what belongs to who and what side of the cage its set on. I'm still relatively new at this too, and have a lot to learn, so at the start I never try to buy something too expensive unless its obviously crappy.