appsfire
Cost: Free
What does it do?
Appsfire is a catalogue for apps, it enables you to see which apps have changed in price. It has a number of different categories of apps, and has built in filters to show apps that are free and apps that have had price drops.
How have I used it?
I use appsfire pretty much everyday, looking through the different categories I have found numerous apps that have had price drops and even gone free. I have saved a lot of money since downloading this app. You can also use it to track apps that you would like to buy, and when they drop in price it can notify you about it.
iTune direct download link
https://itunes.apple.com/gb/app/appsfire-free-your-daily-dose/id418295945?mt=8