How do I mirror my iPhone screen to my MacBook Pro for free? I am using a 13 inch Retina MacBook Pro with Yosemite and an iPhone 4s with iOS 9.

I want to record game tutorials. 
I've tried to use the QuickTime Player to screen record but the little arrow on the right side of the record button doesn't show my iPhone video, only the microphone. 

Is there any good, free way to do it?
QuickTime Player can only mirror iOS devices with Lightning connectors.  If you want to mirror an iPhone 4s, you'll need to purchase one of the AirPlay Mirroring apps like AirServer.

According to this support article (emphasis added):


  Movie recording works with your built-in camera and many external cameras. If you're using OS X Yosemite or later, you can also record the screen of any iOS device (iPhone, iPad, iPod touch) with a Lightning port and iOS 8 or later.