The Pro version of Showbie has a lot of extra features to make your classroom workflow smoother. Here's how you can upgrade to Pro:
Tap on the Get More with Showbie Pro message at the bottom of the app
You can scroll through the popup messages to view all the Pro features
Tap on Buy Pro Now
You'll be prompted to confirm and to enter your Apple ID password
You'll be taken to the Apple App Store to enter your credit card information to confirm the purchase
Once done, you'll receive a confirmation email from Apple and that's it - you'll be upgraded to Pro!