Just a tip, if you have not already then make sure you register a business. That way you can add all of your expenditure (like PPC costs) as a deduction so you will not pay tax on it
But I know LLC, I pay one time fee for taxes no more then that, No paper or proof as long I am not doing business on that state or have workers in state.
That's any business, you can do that as an individual. Obviously if you spend $50 to make $80, you only pay tax for the profit ($30)
For An LLC I do not think there is taxes, unless there is customers in same country or worker in same country that LLC has been formed, as far as I know.