The limitation of this App is that you can send only 100 character long SMS. How to Send Free SMS via Facebook:
-Login to your Facebook Account and go to ChatsSMS Application. -When the Request and Permission window opens then click on Allow button. -In the next window select the country and country code where you want to send the SMS. -In the Phone Number field give your Friends mobile number and in the SMS text field type your message that you want to send. -After this click on Send SMS button and your SMS will be delivered within few seconds.
