I carry the ACR ResQLink. It has some limitations and lacks some capabilities other alternatives have, but other than an iPhone, that is all I carry. You have to be alive and mobile to activate it, which is why it should be carried on your person. It obviously won't help with tracking the aircraft to the point of impact. Other than the emergency transmissions on 406, 243.0, and 121.5 MHz frequencies, it has no other communication methods. The emergency locator transmitter installed on most airplane is a backup, but those work in less than fifty percent of accidents.
There is no subscription fee, but the beacon does require initial and recurrent (every two years) registration with NOAA.