Lots of providers are happy to provide worldwide service for free, as long as you pay $10 per gigabyte. I generally budget 1 check-in per day, of about 250 bytes, so a coin cell can easily power it for a few years with a total service cost for 2 years of just a few cents.
￡0.96 | DIY KIT GSM GPRS M590 gsm module Short Message Service SMS module for project for Arduino remote sensing alarm https://s.click.aliexpress.com/e/b4tPrIy0
Lots of providers are happy to provide worldwide service for free, as long as you pay $10 per gigabyte. I generally budget 1 check-in per day, of about 250 bytes, so a coin cell can easily power it for a few years with a total service cost for 2 years of just a few cents.