99cents K type thermocouple

Seller says that the max temperature is only 300°C but that's because at higher temperatures it damages the heat shrink tubing that is at the end of the probe and the "fabric" around the wires.
But no problem for the actual thermocouple, you can go up to 1250°C, after that you'll start to damage it.
Here it is:
(it's a "search link" since the seller frequently removes and re-creates the listing)