PLEASE NOTE - the AQWorlds linking is no longer working for BattleGems, AQDragons and Undead Assault. AQDragons and Undead Assault are not available via the Google Play store any longer.
AQWorlds will be adding packages for BattleGems and Undead Assault in the future that players can purchase to obtain those game specific items. The Flame Dragon Warrior package for AQDragons is already available for purchase via AQ.com.