The free to play business model can be extremely successful for game developers, especially if you are able to convince players to pay upwards of $500 for a single in-game item. Mobile phone game maker Glu offers a title called Gun Bros where the top weapon in the game can be purchased for the equivalent of $500 real-world dollars.

Gun Bros is an overhead dual stick shooter for iOS, Android and Facebook. The game was released for free in October 2010 and features a robust in-game marketplace where you can upgrade weapons and armor.

According to TouchArcade, users can purchase upgrades two ways. The first method is by utilizing a coin currency which is generated for you at the end of a level based on your performance. 

Impatient gamers that want to advance through upgrades more quickly can purchase optional "war bucks" using real-world money. Additionally you can view in-app advertising or sign up for special offers to earn war bucks without paying anything.

If you have your heart set on the top gun in the game, called The Kraken, be prepared to view a lot of advertising or shell out a ridiculous amount of money to the tune of nearly $500.

The largest war bucks package sells for $99 and gives you 710 bucks to work with. The Kraken can be yours for 3499 war bucks, meaning you would need five $99 packs if you hadn't already earned some through in-app ad participation.

Perhaps one of the eight people who bought the I Am Rich app a few years ago might be interested in The Kraken. At least this time they would get something useful for their money.

What is the most money you have spent on in-game purchases or DLC?