Advise on thermocouple

Hi,

I want to calibrate my heatbed. I will be getting a silicone heater with a 100k ntc termistor inside. i'm thinking of sticking it on a 5mm think glass.

I know that the thermistor will be inside the heater and not touching the glass so I want to find the final heat on top of the glass.

anyone have a advise on a thermocouple that I could get ? maybe one that i could connect to my digital multimeter ? (not a Fluke unfortunately)

Thanks

J-F