jrdoner:
I've used little under $1 thermocouples in many places, using the SteinHardt-Hart equation (think that's the right spelling) to covert resistance to temperature. They're durable, reliable, and accurate.
No you didn't. thermocouples output a voltage and have an almost zero resistance. Each type of thermocouple has a large polynomial you use to convert the voltage to temperature. You used a thermistor - which might be an option, but not what the OP asked for.