Where Do I Add My Promo Code?
If we happen to be running a holiday special, and there is a promo code available for a discount, you would add it to the first page of the checkout area in the Discount Code box, then click Apply. The code will only work if there are no subscription items in the cart. Promotional prices are for one-time use purchases, and can't be the rate for future subscriptions.
If you want to place a subscription order as well, please consider placing a second order for the subscription alone.