PSN is a worse version of the PC client, never play games on a console that are available on a PC just for future reference. There are very few titles that aren't better on a PC compared to the console version. One of those lessons we all have to learn, like not to preorder.
Selling cards is already barely worth the work to send them via mail, using the AH is definitely not worth it for most people but hey, more power to ya if you find someone willing to deal with the AH and this definitely flawed system for marginal monetary benefits. I'd rather put my face in a meat grinder than touch the auction house ever again personally.