Gilded Chest

Gems (iOS) and GREE coins (Android) are what is used to purchase items in game.

The cost of in-game items is the same for Gems as it is GREE coins, so let's look at the per 1 USD$ ratio for each of the prices of each currency.

Conclusion:

Android stays the same rate, and can be bought in cleaner increments (so you don't get change left over)

However, the best deal is to buy the $22.99 Gem pack on the iOS version, with $14.99 coming in a close second.

The fact that the most expensive is the 6th best deal... well, we're not here to comment on business practices, just look at the numbers.

Good luck everyone!