It's very easy to wire up a Ranco or Johnson thermostat and there are plenty of instructions online with pictures on how to do so. You can save yourself about $20 if you have a little wiring know-how and don't want to pay for someone else to do it. I always bought pre-wired in the past, but i realized how easy it is and wired up my last one. Took me 5 minutes and works great!