Satellite communications really fall into three categories. There are the basic systems like GlobalStar. A very capable network which receives very short messages from devices globally and forwards them via ground stations to the cloud. The communications is inbound only usually not more than once an hour.
Then there are the most sophisticated systems like Iridium, where they give a two way messaging capability, albeit at a considerable price. Similar to GlobalStar is that there is a cost per message so like a mobile phone there is a monthly bundle of messages and or data sold per device. Prices tend to be in the tens of pounds per month category. Running a satellite network is not cheap and global communications means you need a constellation in orbit.
Finally, there are the systems that range from Inmarsat through to satellite broadband. These are not man portable solutions but tend to be fixed installs, on the ground or in vehicles. Data is sold by the MB or based on the ‘pipe’ or bandwidth.
All three sorts of solutions have their place. However, then are naturally more expensive that comparable terrestrial networks.