Yeah, it really costs $100k. Custom Iridium devices of this character aren't terribly expensive, on the order of $500k to $1M to design and $5k-$10k each to manufacture in small quantities. The rest is the cost of putting it on the plane, maintaining it and paying for satellite service.
Iridium is an LEO satellite constellation. You only send the radio signal a few hundred miles, you you can basically point an antenna generically at the sky and talk. It doesn't require the kind of complex engineering that talking to a geostationary satellite from a moving vehicle would.
The report didn't say, but a device of this nature is most likely what was on he air france flight, sending in the maintenance reports.
Nevertheless, $100k is a lot of money. Would the passengers have been willing to pay more for the tickets so that their loved ones would have a slightly better idea where they crashed? Probably not.