We are often asked, "How much data does the Lone Worker app consume?"
A typical message is approximately 8Kbytes. The size of a message can vary a little depending on the type, but you should use this a the rule-of-thumb.
Therefore, if you are in tracking mode, sending a position report every hour, for 8 hours a day, for 20 days a month, then you will consume approximately 1.2Mbytes from your data plan in that month.