Sale has ended but you can still get this app.
Download Flip Text Pro – Upside Down Now

Official Description

Wondering how can your friends send inverted or upside down messages?

Now you can also transform your text upside down.

Get free version at https://play.google.com/store/apps/details?id=abhi.fliptext

You can send flipped messages to your friends by SMS, email, Facebook, WhatsApp, Twitter, etc.
Works with all messaging apps (eg. Whatsapp, SMS, Line, Skype, Wechat, email and more!)

You can also copy to clipboard and use it for Facebook/WhatsApp status or tweet.

Your friends will wonder how you made those stunning messages .

Have fun :)