I think there are several Acurite or similar ones that can be had at a VERY reasonable price. Some even have a probe for a secondary reading. Mine cost $8.55 on Amazon. I don't think we are supposed to link to products for sale, but if you search for Acurite thermometers, a ton will pop up and you can read the reviews on them

Honestly, the picture with the snake on top of your meter is making me nervous. The humidity in the enclosure and the weight of the snake can definitely make it pop off, and not necessarily at the "velcro" point. That is a big piece of adhesive that your BP could get stuck too. You can get it off with mineral oil, etc, but it often causes damage to the snake, not to mention the stress. Just test it real well and often until you can find something better.