First in cydia you need to install repo for sinful iphone repo / google it you wwill find the repo
Then you search for iAPfree... download it and install it
After enabling it , you can make in in app purchases in most apps for free in games and apps like injustice, jazeera sports etc.
Enjoy..
![out :out:](./images/smilies/icon_out.gif)
![out :out:](./images/smilies/icon_out.gif)