Which payment methods can I use?

More detail

Apply a promo code before you pay; the discount shows in your order summary before the charge goes through. Kreds and referral credit apply the same way. See Applying a promo code or discount and How Kreds and referral credit apply to a purchase.

You don't have to tell your bank first, but it can save a declined card. Most banks treat the purchase like any other online payment. Some run a fraud check on a travel purchase, a first purchase with a new merchant, or a purchase made from abroad. They send a text or app alert to confirm it. Approve it and try again; if nothing arrives, call the number on your card. A decline is the bank's check, not a problem with your plan. Charged, then declined on a retry? The first attempt is a hold that drops off on its own. See Charged twice? Here's the fix.