Why isn't my coupon / offer applying? (And a list of restrictions)

Due to some restrictions with various payment processors, we've prevented certain scenarios allowing coupons or store offers to apply.

• If the final value of the product is between $0 and $1, the coupon/offer will not apply. This is due to payment processor restrictions on values below $1.
• Coupons/offers only apply for the first initial order, it won't apply for future payments (in a payment plan) or subscription / recurring billing payments
• If coupon/offer is applied to a subscription product, Paypal is not available as a payment choice
• If the products in the order are subscription products, coupons cannot bring the value of the order down to zero. This is due to issues with processors processing a charge of $0 and then charging more than $0 for future subscriptions.