Here's how it works: Developers can set a temporary rate that will last for a predetermined period of time. Say you have a cloud storage app that typically costs $2.99 a month. You can now opt to allow new users to get the first three months for a cheaper rate.The thinking is that users will be more likely to pay full price for a service once they have had some time to try it out at a lower price. Google says it expects this change will help increase app subscriptions overall. (In a blog post, Google notes that app subscriptions have increased tenfold over the last three years.)Apple also recently changed its policies around app subscriptions, with any developer now able to make their app a subscription. (Apple is further incentivizing subscriptions with a more favorable revenue split for developers that can keep subscribers for a year or more.) Google's update may seem like a small change, but it stands to have a big impact on developers who may want to offer things like promotional pricing but have difficulty implementing such strategies within Google's developer tools. And that's good news because Android still has a lot of catching up to do when it comes to app revenue. As a whole, Android users spend way less money in apps than their iOS counterparts, despite having a larger marketshare overall.