Countdown Sector 106 on sale atm (Android)

[Pyroxian]

Tinman games' Judge Dredd game-book is current;y £1.76 on the Google Play Store (no idea about iOS)

https://play.google.com/store/apps/details?id=au.com.tinmangames.dredd.countdownsector106

Also, their Trial of the Clone book is also going cheap, and it's good fun (plus it's narrated by Wil Wheaton).