That's a Honeywell T6. It's really easy to replace, theres a separate part that retains the wires that you can keep attached to the wall. IIRC, it's just one screw on the bottom and then it pops off.
You can find open box/used ones on eBay for less than $50. There's an installer menu on these thermostats, go into that and mark down the settings, and set the new one up the same way. You'll find a PDF of the installers manual online that can tell you how to get into the menu, or I can help you.