A: When you first sign up you will be enrolled in your trial period. At the end of that trial period you will be charged for your first month on that day. After that, the same day the following month will come the next charge, and so on.
Example: Started trial on the 4th of a given month. Trial ends on the 17th. First month billed on the 18th. Every month after that bill will come out on the 18th.