A very important way for app developers in paticular of generating revenue without funding. and that may happen in to ways
we all know that we can sell digital goods through the internet , so using google play we can provide the users with some services that has a bill when installing the app, and that will happen once the user has used any payment method before to install a previous app ,they can use the same for yours.
The app maybe a service or a product such as :
cloud software products.
however ,there are many other ways to get paid using google play , one of them is Advertising which means that we can get paid for showing google ads.
finally , we have to follow some tips for the initial monetization; how to attract users to download and use the app ? and why they will use your app not others?