If your app something that people have to pay a monthly fee for? Are you an app that is a subscription service? Does your android app marketing make people want to buy it? If you have an app that people are charged a monthly/annual fee for then you should note a few things.
Your app itself should be free. Extra charges will turn people away from your app. If you charge fees then your app should be free because people will already being paying to use your app.
The price of your fees should make people think they are getting a good deal. Do not lie to your users but being cheaper than other similar services even by a little can make someone favor you over a competitor. If being cheaper isn’t an option then you need to have something your competitors don’t. If you are not unique then why should anyone choose you over the next app?
When you have a subscription based app you need credibility. No one wants to put their credit or debit card on a site that has no credibility or that looks like a scam. If you do not have any credibility you should start off by offering a free trial. This can be a week free trial or so and will let people explore your app without having to put a card on account. This will start to build up credibility when people buy a subscription. After a while your android app marketing will allow you to gain credibility by itself and the free trial will no longer be needed if you so wish.
Using android app marketing will be very difficult if you do not have credibility. Though it can make people interested and they may wait to see if you gain the credibility before downloading and paying for your subscription.
Complete list of Android App Marketing Lessons