The Simpson's: Tapped Out Uses Purchaseable Donuts as Currency

 - Apr 10, 2012
References: facebook & wired
The Simpson's: Tapped Out from Electronic Arts may be free to download, but without purchasing 'donuts,' a player will advance pretty slowly.

Available for iOS devices, the game is similar to SimCity with players rebuilding Springfield after Homer lets the power plant blow up, which destroys the city. While the game doesn't cost anything, certain things can only be purchased using donuts.

Although one can save up donuts by advancing through levels, the sugary snacks accumulate very slowly and those with little patience can instead purchase the snacks from EA, starting at $1.99 per dozen, to speed up game play. The game operates on a pay-what-you-can sort of system where one does not necessarily need to purchase anything, but will be rewarded for doing so.

The game has been so popular that EA has to limit downloads to ensure that their servers run smoothly and users could actually log on to play.