I'm getting four more digital thermostats from Mcmaster Carr. Its a
Johnson controls A419 unit. This makes eight units on my place. I want
to get spare sensors and I'm thinking this must just be a
thermistor??? I see it can be ordered from the maufacturer, but I know
it will be a rip off price. Ideas for Digikey, etc.?

A419 thermostat:
http://www.prothermostats.com/produc...a7K godW3Jdaw
manual
http://cgproducts.johnsoncontrols.co...PDF/125188.PDF
sensor
http://cgproducts.johnsoncontrols.co...ID=A99BB-200C#