With the rise of the mobile internet, more and more developers are turning their attention to apple or google's app store. But for these app developers, one of the questions they have to consider is how to make their own apps to make money, whether to take a free strategy and then make money through other channels or directly charge, this is the decision that developers need to make. Usually, when we ask this question, many developers will put the profit strategy to the end or directly respond to the current failure to consider the profit model.