andrewa wrote:Why can't someone just buy a Sat phone outright, and just buy a sim car when needed?
Yes ... why indeed.
One trick I have seen mentioned. An Australian Telstra SIM (prepaid I think) placed into a Sat phone will work .. both with cell towers and when out of range, Iridium satellites. There is some link between Telstra and Iridium. Most (if not all) Telstra sales persons don't know this or wont confirm it. Of course the call fees are high, but still you are not going to use it often. You might find something on that motorcycle site I linked to above about this.
Sat phones can be purchased secondhand - try ex rentals from the rental firms. Bit more than half price looks to be the going rate.
In the short term renting is the cheapest option. Maybe Bush walking clubs could buy satellite phones for the use of members?
Looking forward ...
The EPIRB/PLBs next generation may include a messaging service where you and send a text message ... might only go to the emergency services so they can tell what kind of difficulty there is before they arrive.