Ring is a Social App for Sending and Receiving Text Messages

Ring is a social app for sending and receiving text messages. With it, you can send a message to a single contact, or you can invite your friends to chat with you. This is the best messaging and social chat app that is available on Google Play for Android.

You can also call friends and send them a message and share a photo, and you can also send them a sticker that you love. 

Ring+ is a premium version that offers the following:

In-App purchases for credits or tokens. Unlimited messages and messages are free. Invite friends and receive a bonus when you invite them. Ability to add friends to the phone book. Unlimited SMS credits.