Reinstalling iLife Suite after erasing hard drive and reinstalling OS X

I received a Mac Mini from my father after he was using it for 6 months. After receiving the computer, I had to reinstall OSX after erasing the hard drive. On the reinstall, all of my iLife Suite apps were no longer installed. I went to the App store and now each app costs 19.99 USD for me to install.

Any help on restoring these apps?

I'm running El Capitan and the Mac Mini is the late 2014