Hi
@peterg, I would say own.
I'm on my second sat phone. The first one was on the Globalstar network which worked very well, but then had some issues with their network.
I recently purchased an isatphone pro.
These operate on the Inmarsat network for around the $650 mark, and you can also purchase pre paid air time for them. (The isatphone pro is their older model so can get reasonably cheap. The new one is isatphone 2 at around $950)
I just purchased a 3 month $70 credit for our recent trip.
Will recharge again later in the year for the next one.
No monthly charges.
Highly recommended.
Have a look at
http://www.asta.net.au/satellite-communications-products/isatphone-pro