How much can a top mobile game make off of ad-network sales? If Fruit Ninja is any indication, about $400,000 a month.

That's the ad revenue that the popular video game grossed in April on the free versions of its iOS and Android games by selling its inventory on Mobclix, a mobile ad exchange. Mobclix's technology lets a bunch of different ad networks bid against each other to place ads on mobile apps. Phil Larsen, CMO of "Fruit Ninja" developer Halfbrick Studios, said that while the 60-person company wants to control what types of ads appear in its games, it doesn't have the time or resources to manage the process itself.

"We want as much control as possible, but the more control you have, the more micromanagement that is needed and we don't have the bandwidth in-house nor do we really want it," he said in an interview. Mr. Larsen said the game could bring in more ad revenue if it allowed "spam ads for dating sites and things like that …stuff that doesn't have value." Instead, it works with Mobclix to filter out what it deems lower-quality ads.

Mr. Larsen acknowledged that while $400,000 a month is a decent chunk of change, it's not an exorbitant amount for a game that is as popular as "Fruit Ninja." But luckily for Halfbrick, the majority of the game's revenue comes in the form of downloads of the paid versions of its games and in-app purchases -- not advertising. "People see ad content and free content rising and think it must be at the expense of paid [apps]," he said. "At this stage for us, it's not true."

The paid version of "Fruit Ninja's" iOS app (which doesn't run ads), for example, is currently on the Top 10 list for paid apps on the iPhone. As a result, "Fruit Ninja" grosses more than $1 million a month in total revenue across different platforms, Mr. Larsen confirmed. Still, the Brisbane, Australia-based game company doesn't completely outsource all dealings with marketers. Mobclix handles all the selling of ad units, but Halfbrick works with marketers on bigger brand integrations. One such case saw Halfbrick partner with Dreamworks on a special Puss in Boots iOS version of "Fruit Ninja." Mr. Larsen said more of those types of deals are in the works.