Apps on the App Store go free everyday. The problem is there are over 700,000 apps so finding the apps which have gone free is ridiculously time consuming task.
AppsGoneFree is a brilliant app which lets you know of some of the great apps which have gone free today. It won't just show you any app which has gone free, only the apps which are of high quality and you can use.
One of the best features of the app is that it notifies you when the list has been updated. So you don't have to remember to go back to the app to find apps which have gone free today, you'll just be reminded.
I've got myself some great apps for free using this app and there are some real gems which pop up now and again.