You can send SMS from your mobile phone using the formula =SENDSMSWITHMOBILE
The price per SMS is the one from your mobile phone carrier.
You need to download the mobile application: https://play.google.com/store/apps/details?id=io.sheetsms You can send 10 SMS per day with the mobile application but if you want to send more you need to upgrade for 10USD a month
You can send SMS directly from your Google Sheets spreadsheet using =SENDSMS or =SCHEDULESMS
These formulas send SMS using a random number or a custom sender name. The price per country can be found below:
One SMS unit is 124 characters of english alphabet. If you include non-GSM characters like eastern characters in SMS messages, the size of one message is 39 characters.
If your SMS is bigger than the size limit, you will pay the price corresponding the number of units in your message.