Cheap alternative to Thermocouples?

Unless you really need such a wide sensing range, the Dallas 1-Wire chips are MUCH better... at not a great deal more complexity to use.

DS18B20 range: -10C to +85C

Yes... they take a little "getting to grips with"... but once you're there, you have an easy, reliable, high prescision... at the end of long wires... sensor.

And "DS1820" must be code for "Viagra" for the number of auctions you'll find on eBay for the things!