Sellers will sometimes offer the option for prepaid subscriptions, which allow you to pay for several subscription renewals and shipments up front. This usually results in paying less on a per month basis than if your subscription renewed normally each term.
Since the entire prepay term is paid for up front, you will pay the aggregated shipping cost of all the shipments. You will not be charged again for any renewal or shipments through the course of the prepay.
Prepaid subscriptions renew at the end of the prepay term for the original term length. This means that if you initially subscribed for a 3 month prepay of a monthly subscription, it would renew for an additional 3 months at the end of the subscription term.
Lastly, it's important to note that if you change your product or term for your subscription, the changes won't take effect until the prepaid subscription term ends. This is because that prepay and its shipments were already paid and accounted for. If you want or need to make a change immediately, you can always contact the seller directly with any questions or for assistance.