Saw Sopranos Pizza Mosman had an ad on the door saying free pizza with the iPhone app. When registering on the iPhone app it appears its a buy one get one free, which is probably a good thing as it would most likely be ozbargained if it was a free pizza with the app.
So, it looks like the deal is effective on the app and the website, and for first time orders only.
Deal has probably been around for a while.
iPhone app
https://itunes.apple.com/au/app/sopranos-pizza-mosman/id6095…