It took them billions to disrupt those markets, thousands of staff and a lot of uphill struggles before they started making a profit. Either no effective solution exists, or the current solution has serious shortcomings. If you want to go one level deeper and be more exact, find out the cost per activation, keeping in mind that there will be a percentage of users who might install the app, and then uninstall it without engaging with the app.
If you want to charge users using one the these models you will need to test your pricing by figuring out how much users are paying for a similar service, or the amount of money they are paying to solve the problem your app seeks to address. Costs Investors need to know what everything is going to cost and what the variables are.
You can choose any variables that accurately slice your competition for the X and the Y-axis. Financials Now is the time to sit down and crunch some numbers.
For Android users, they've got the choice of over 2. Give details on how they got involved, their role and responsibilities, along with academic and professional experience in mobile application development or related fields.