At the time of purchase, you will be charged the complete current advertised pricing (minus any coupons or discounts used) for the number of boxes (and any applicable shipping costs) in the plan type and length you choose. Your first box will ship according to our subscription shipping schedule. Your renewal will process on the 9th of the month after the last box of your subscription (e.g. your last box is March, your renewal will process April 9). Renewals are charged at the advertised pricing at the time of renewal and are not based on the price paid at the initial purchase.
For information on managing renewals see here.