Say if it got one million downloads. How much money i have to pay per month.
about 10 years ago
You can monitor usage in the analytics portion of your web console at any time. We bill on a monthly cycle, so if you go over the 100 user mark and are in the paid bucket, we send you a billing notification at the end of the month, and you put in your payment info in the console. Your app won't be affected unless there is not payment info.
If it turns out your app is highly successful and you're getting tens of thousands or hundreds of thousands of new users each day, we typically get in touch before the billing cycle is closed to work something out.