You will receive your first bill shortly after you started using the service.  Usually after the first week.  The first invoice will include the set up/tutorial fee.  Every subsequent invoice will always be the same amount unless you  suspend service.  In that case it is pro-rated.  Please know that by using the supplies you are using the service.  So if you go on vacation and use supplies, you are using the service.  If you have pre-paid or use a gift certificate you will still receive an invoice  that is  marked as “Paid” and clearly shows how long you are covered for.