/r/financialindependence : This is a place for people who are or want to become Financially Independent (FI), which means not having to work for money.
/r/personalfinance : Get your financial house in order. Learn how to better manage your money and debt in both the short and long term. Find out how to save an emergency fund and invest for your future.
Android Studio : The officially supported IDE for Android development. Most modern tutorials should be using this now, including Google’s.
techotopia.com : Great resource with explanations, examples and images to teach most things you need to develop an app (this link is about in-app billing for example).
/r/androiddev : News for Android developers with the who, what, where when and how of the Android community. Probably mostly the how.
Google Play developer console : Your home for publishing and managing your apps. You can manage all phases of publishing on Google Play through the Developer Console. Using any web browser, you can upload apps, build product pages, set prices, configure distribution, and publish apps.
Google Merchant Center : Google Merchant Center is a tool that helps you upload your store and product data to Google and make it available to Google Shopping and other Google services.
Google Firebase : The tools and infrastructure you need to build better apps and grow successful businesses.
Google Admob : AdMob offers advertising solutions for many mobile platforms. To host and manage ads in your apps.
Google Adwords : Google AdWords is an online advertising service that enables advertisers to compete to display brief advertising copy to web users, based in part on cookies, keywords, predefined by the advertisers, that might link the copy to the content of web pages shown to users.
GetJar : Alternative app store to publish your apps and get more visibility.