Hi, my name is Daniel.
I am experienced software developer, in particular solutions related to embedded development (cloud devices or such with connection via Bluetooth, USB, RS232 etc.)
I can implement your project using wavecom modem. Another option is to use some cloud service to send bulk SMS messages, such as Twillio.
I just performed a rough calculation, according to Twillio, 50 SMS cost to send is 0.38 usd. That means if you send 50 messages per day, you will get arround 11 usd per month.
Both methods have advantages and disadvantages. Please contact me for details.
Thanks,
Daniel