How to transmit data over a long distance at a affordable price
If you do not want to customize hardware on the smartphone side your choices are limited to, largest range on top:


Iridium network. (satellite internet)
LoraWAN. (long range 433 Mhz Internet of Things)
Text messages.
Cellular internet.
WiFi.


If you do want to create custom hardware on the smartphone side, you could see if any of the amateur radio bands suffice, or possible the semi-unlicensed 400/800 MHz ISM bands.

Or maybe microwave beam connections. Like Mikrotik RBLHG or Ubiquity.

Your question right now is quite broad and does not show much research. Maybe start googling with the above.