|Magellan satellite phone and GPS.
The phone costs $3US a minute to use. When my Mexican tourist visa ran out, I went to the US and left the phone with a Canadian friend living on the beach near Mazatlan. I returned to find he had loaned the phone to a bunch of people in the village, and I had to pay over $1000 in air-time fees. When I asked why he did that, he said, "I thought it was free... because how would they know where to send the bill?"
Several months earlier, Stratos, the air-time provider, sponsored me with $1000, but half the funds were already used while testing the phone for receiving email, so I still owe Stratos $600US.