cheap thermocouples. Homemade?
Wire ends can be twisted together without any problems.

I performed an experiment as part of my undergraduate coursework where we used twisted pair of copper and constantan wires (twisted part about 2cm in length) that were held in place mechanically. It worked quite well. The temperature range was about 100-300C, so that should be right in your ballpark.

When you twist the wires, you have to make sure they are twisted around each other, not one twisted around the other. The best way I found to achieve this is to bend each wire 45 degrees, so they make a 90 degree angle with respect to each other. Then just hold both wires and twist.