That “kid” technician probably googled “thermocouple replacement” on his phone more than he worked. You’re lucky he didn’t try to sell you a whole new furnace.
$200 for parts and labor is actually a fair price for this. Thermocouples are inexpensive ($15-25) but the labor to diagnose, turn off the gas, and correctly seat the new one adds up quickly. And you’re paying for the peace of mind that it’s safe.
Smart move not waiting for the quote. When the mercury drops, you want that heat on, not in limbo while someone checks their inventory. Keep warm! 🔥