snakes handle cold temperatures much better than hot ones; your bby will be fine for a few days without a UTH as long as your ambient temps are okay.
many of us use AcuRite digital termometers/hygrometers. here's an amazon link for the one i use but you can find it at walmart. AcuRite also makes digital thermometers that have a probe, so do a little research to figure out what you need.