According to publisher NaturalMotion, free-to-play racing game CSR Racing is amassing $12 million per month in the iTunes App Store. The 3D racer is monetized through in-app purchases like premium cars, though it's important to note that it only launched at the end of June, so the current figures represent around six weeks in Apple's mobile marketplace. According to CEO Torsten Reil, the early success of the game is in spite of the fact that the publisher has spent no money on marketing.

"It's all organic downloads," he told Pocket Gamer. "Word of mouth is the acid test for us." In comparison, Epic Games' Infinity Blade II — which the company says is the "most profitable game we've ever made" — made $5 million in its first month on the App Store. With numbers like these, it should be no surprise that a number of notable developers are switching over to the free-to-play model.