A PLB is worth it if you can afford it. AFAIK there are no ongoing fees, but your particular location might have rescue fees if you use the beacon. The beacon communicates with satellites to a global centre that then sends your details off to both the national centre where you registered the beacon and to the national centre where the beacon went off. When I registered the beacon I supplied the contact details of a few people. These are the same people I tell my plans to when I go somewhere. The signal includes your GPS coords down to a hundred metres if the GPS can get a good fix. This particular model also has a radio pinger to allow rescuers to zero in on you once they get close. That's super awesome if you go non-responsive after activating the beacon.
It is frightening being lost and much easier to do than people realise. I sorry to hear about your colleague. Exposure is a massive killer in the outdoors here too. I've been changing my outdoors clothes to wool baselayers and including some warming solutions. In this particular kit there is a tea-light candle. Light that sucker, place it in the canteen cup and then put that canteen cup between your legs and sit under the poncho. It's surprisingly warm!
My own lost story is on steemit: Lost in the dark, mistakes were made.