Trouble re-downloading paid Apple apps bundled for free with new Mac

I recently bought a 13" retina MacBook Pro. I set it up with my Apple ID. I subsequently changed my Apple ID password on my iPhone. When I came back to log into the MacBook, it wouldn't let me with my new password. So I tired my old password which didn't work as well. I performed a factory restore on it and that seemed to work. But I then noticed that it deleted certain apps that where already installed on the computer such as iMovie. When I go to the Mac App Store to re-download them, they are shown as paid apps. How do I download them again for free?