PLBs cost around $300 [1], they have five+ year batteries, and they don't require a subscription. If you need to use it, you turn it on, it grabs a GPS lock and transmits your coordinates for about a day, during which at least one satellite will see your signal and downlinks all over the planet will log your location. It may still take some time for rescue services to get to you, but finding you will no longer be the primary concern.
If $300 is still too much, you can usually rent or borrow one for the duration of your trip. Just throw one in your backpack and consider yourself lucky if you never end up needing it.
The nature of emergencies means you don't know what you're going to run into. You could be lost, you could have a broken leg, you could have been bitten by something lethal, you could be treading water 100 miles offshore. You could have provisions for a month, or you could need a medevac ASAP.
If you actually have an emergency, do you want to sit around for a week and hope that you get noticed, or do you want rescue services all over the planet to have your exact coordinates within the hour?
Ten years ago these might have been newfangled novelty gadgets, but today they really should be considered required safety equipment if you're going into an area that's remote, or where there's a real possibility of veering off course. If you're sailing a boat or flying an airplane, they're usually legally required now too. They may not be mandated for hikers or backpackers, but don't be an idiot -- you need to have one.
Rescue services don't look for lines in the sand or messages in bottles anymore. The world spent over a billion dollars to get the Cospas-Sarsat program up and running, and the expected method for signaling distress in 2020 is by satellite. You should have the equipment to make a distress call if you're going to be in a position where it may be necessary.
Don't needlessly make things harder on yourself and on rescue workers by thinking that it's manlier to flash a mirror at an airplane. That can be your backup method, but not your primary.