In this video from mez380 he shows how to install Installous which allows you to download any app store app for free for the iPhone. In Cydia you go to Manage, then click Sources. Now in the upper right click Edit, then Add. A box will pop up now asking for an address. Here you will type in cydia.hackulo.us and click add source. When it is done you will see Hackulo.us pop up. When you see it, click into it and scroll down. You should see Installous there in the list. Now you can press Installous to use the app and find apps for free.