If you know what you are doing and reasonably competent it is fairly easy. Depends where you live but in NZ you can get a thermostat from F&P for around $50 -$60. There are cheaper alternative thermostats available which work just as well for around $35. Using the cheaper alternative thermostat should cost around $90 for a service person to do it. Any more than that & your getting fleeced. If your living in my area that is. Charges where you live may be completely different.
Lincoln Appliance NZ, June 2010