Hi Terry,
You're right regarding the Spot device, which has a special satellite network (and not full global coverage as they declare themselves), but the FastFind device (just like many other expensive PLB devices) has no yearly fee, well, no fee at all - even registering your device is free.
"The FAST FIND 210 GPS PLB transmits the two signals simultaneously, one to the subscription free global 406 MHz satellite system, and the other (121.5MHz) is to speed up the local recovery response process."