in which country as you ? There are some other webservices that are exposed and they are avaiable in certain countries not all and they have limited credit because everyone uses them, so i will conclude by saying you can send an sms for free , you need a gateway , and a gateway can only be provided by Service Providers like your web hosting company, Mobile Company and other Sms gateway Service Provider like
root = tkinter.Tk()
buttons=[i for i in range(10)]
#If specific button is pressed, output "YES"
for num in buttons: