I would say invest in a PE-2 temp gun. It cost a little bit more than a basic temp gun, but is an invaluable tool for herp keeping. It has a laser pointer, and can measure a much wider range of temps than you will ever need. They run about $45. You can find these on Pro Exotics website, and some other people offer them for sale sometimes. I bought mine from Neil Golli, with the carrying case shipped for $55.