Out of curiosity, can you share more on your pricing strategy? What is actually paying for your development? It looks like you give away a lot for free, do you

Out of curiosity, can you share more on your pricing strategy? What is actually paying for your development? It looks like you give away a lot for free, do you do that cause the server costs are nil without e.g. sync? Can you share the rough number of users in each tier/service?