We had better define "cheap" - a glance at the REI catalog showed PLBs ranging in cost from $150 to $500 - the more highly rated units being toward the high end. There are also subscription services required to fully utilize the capabilities of the units/

These units are definitely not foolproof in real world usage -lots of tales about their various glitches.

I admit I am a bit of a dinosaur. I kept out of trouble for 60 years without a PLB. They are not high on my priority list...