title: SMS authentication for a website
body: <p>I'm looking to implement an SMS authentication for one of my projects, basically before a user is able to register an account with us, we would like to authenticate the user by sending sms containing a code to his mobile phone, and get him to put in the code in our form before he can proceed.</p>
  
  <p>I've been looking around and found onVerify to be a pretty good way to go
  <a href="http://www.onverify.com/" rel="nofollow">http://www.onverify.com/</a></p>
  
  <p>But I'd like to know if there're any other alternatives similar to onVerify as it is a bit expensive, so if I could go with cheaper one, that'd be great.</p>
  
  <p>Thanks!</p>