Board Thread:Game Discussions/@comment-198.255.133.71-20141010005453/@comment-24438936-20141017015443

When they had Soulshard Necromantle as a reward in the arena the first time, rank 1 (on Android) spent 4500 or so gems. It might be less depending on the epic you go for. You can also decrease the amount of gems spent if you buy arena energy when they have those 30% more energy or w/e sales.