AppAddict is a fairly new and is being considered as one of the most recent Installous alternatives. While it may not be as old as the other .ipa installers, it has created an unshakeable fan following of its own in the jailbreak community. There are a lot of people who have started liking AppAddict and find it to be a great place to look for free apps.
Needless to say, AppAddict requires a jailbroken iOS device. If you already own a jailbroken device then you will be able to proceed quickly, but if you do not then jailbreak it first. Next, you must ensure that Cydia is installed on your iOS device. This is necessary for installing AppAddict.
The next thing is, that if you do not have it already, then you must install AppSync. You must make sure that the AppSync version that you are installing is based on the iOS version that you are using. Users who are on iOS 7 must install AppSync iOS7+. Keep in mind that installing the wrong version of AppSync can lead to problems for the device. Similarly, there are new versions for all new versions of iOS, so make sure that you find the right version depending on the device that you are using.
How to Install AppSync
Now open Cydia and go to Manage and then Sources, then Edit and finally tap on Add. This will bring up a text box where you must add a repo which has AppAddict. The best source for AppAddict is xsellize, so use this link http://cydia.xsellize.com. Now once Cydia verifies the link, go ahead and tap on Add Source so that the repo can be added to Cydia. Now you will get the option to Return to Cydia and you will find yourself back in the Sources page.
Here, you must tap on the repo you just added and choose the correct version of AppSync depending on the firmware you are using on your iOS device. Once you have installed AppSync, tap on Respring so that you can be taken back to your home screen.