>>willis+(OP)
Yes, me too. But Iridium recently (2017-2018) launched the new constellation that they call Iridium NEXT which supports L-Band and offers significantly more bandwidth. So, it's now possible to get a 1GB plan for ~$1300/month ([2]). This obvisouly means that one needs to use a different modem. RockBLOCK modems are great but limited to the Iridium "Classic" with these tight limits and insane prices (~$1/KB).
>>willis+(OP)
This is using the next-generation Iridium network which is capable and marketed for offshore maritime, for aviation purposes, land mobile data, land based portable terminals (where people would previously need an INMARSAT BGAN), etc.
It is still very costly on a dollars per MB of data transferred basis.