The High Temp Wire Probe is a good low-cost high temp probe for ovens and backyard grills. It's protected with a fiberglass insulation, however, you should avoid using it over 660°F. Avoid direct immersion in liquids or direct contact with food. Available in multiple lengths.

Specifications

Sensor Range: -77 to 660°F (-75 to 350°C)
Cable: -77 to 660°F (-75 to 350°C)
Time Constant: Less than 0.5 seconds typical in liquid. Less than 2.5 seconds full reading.
Accuracy: ±0.9°F (±0.5°C) from 32 to 212°F (0 to 100°C)