PayPal's official eBay store offers 20% off select iTunes Gift Cards:

Use this discounted iTunes credit to save on movies, apps, music, and more. With the holidays coming up, you may want to grab this deal as a gift. 20% is one of the strongest discounts that ever comes around for iTunes credit.

Gift cards will be emailed so you'll be able to start downloading discounted iTunes media sooner rather than later: "In most cases, this will be within a few hours of purchase. However, in some cases it may take up to 24 hours." US only. Read more of this post