Are magazine subscriptions only paid by credit card??
Yes. Individual issues can be charged to a gift card. Subscriptions cannot; they will be charged to the default credit card every month.
Yep, and this is why I won't take a subscription for a magazine on my nook. I have reluctantly bought a few single issues but until I can purchase a one year or other set time limit on my gift card for a magazine I won't be buying a subscription. Just don't want my credit card dinged for subscriptions every month.