There are cheaper alternatives. A basic SIM800 based board can cost just above $3 on Ebay, probably less on Aliexpress, or less than $10 for a similar one with

There are cheaper alternatives. A basic SIM800 based board can cost just above $3 on Ebay, probably less on Aliexpress, or less than $10 for a similar one with Raspberry PI compatible connections (useable with other systems as well). Also interesting is the SIM7600 module which supports 4G LTE down to GSM plus GPS. Also available in Mini PCI-E boards. https://www.ebay.com/itm/191879410081 https://www.ebay.com/itm/191879410081 https://www.ebay.com/itm/292237166116 https://www.ebay.com/itm/292237166116 https://www.ebay.com/itm/293802495042 https://www.ebay.com/itm/293802495042