If you play any other games where you buy virtual currency, consider using Shattered Crystal. I have an affiliate account with them, and they give a small kickback for going through our affiliate link. They don't have any current PWE cards, but they do have others.
I would like to have some contests with Zen prizes using this method. So, if you do and want to give it a go, here's the link.
Shattered Crystal game curency