Here are some good alternatives to Twilio.
Communication that just works. https://www.nexmo.com Any country. Any volume. Any scale.Connect to phones globally in minutes using Nexmo’s SMS and Voice APIs. Viber, Line and Kakao all rely on Nexmo.
SMS Sheep is now fully integrated with Facebook and is a great alternative to Nexmo. You can send free unlimited text messages.
http://www.cdyne.com Cdyne is another great alternative that is at 1cent and they are working on a post pay option too so you don’t have to pay until you sent the message.
http://developer.hoiio.com Add Voice & SMS into your apps. Easily.