Amazon has launched a new alternative Android app store that uses a payment model that is radically different than any of its competitors. Called Amazon Underground, it promises users apps that are "actually free," which not only means the apps don't have a purchase price, but also that in-app purchases are also free of charge. Instead, Amazon is paying developers directly for every minute users spend in apps. Specifically, developers are making $0.002 per minute, or 12 cents per hour.
Why is Amazon willing to pay developers for the time users spend in their apps? In order to get to those apps, users have to wade through a lot of advertisements for Amazon products. It's also worth noting that Android users can't get the Underground app through Google Play; instead, they'll need to download it from the Amazon website and tweak their security settings to allow the download.
Mobile development firms who are interested in signing up should visit the Underground Developer Site, which includes a revenue calculator to help you figure out if the payoff will be worthwhile.