It's not a coupon or a promotion. It's an alternative payment method so that Mulvad does not need to store any identifying information about its customers. See

It's not a coupon or a promotion. It's an alternative payment method so that Mulvad does not need to store any identifying information about its customers. See https://mullvad.net/en/blog/2022/6/20/were-removing-the-option-to-create-new-subscriptions/ https://mullvad.net/en/blog/2022/6/20/were-removing-the-opti... for information about the situation they are mitigating.