This has other gift cards as well, but you can save on PSN and Xbox Live gift cards.
http://www.ebay.com/sme/paypal_digi...d/so.html?_nkw=&_soffid=5006937604&_seedid=-1
http://www.ebay.com/sme/paypal_digi...d/so.html?_nkw=&_soffid=5006937604&_seedid=-1