Actually, I'd later find that Sony's main PlayStation website does still sell memory cards. I guess they only sell them online. But I did wish I'd known that before I'd gone the eBay route. You see, the second part of this story makes it even crappier. Once I realized that the card wasn't working, I got online to contact the seller about it. When I arrived at eBay, I had an alert saying that the seller had filed a dispute against me for not paying for the item. Apparently my money order must have gotten lost in the mail (and I found it costs about half of what this money order was worth to file a claim about it). I don't know why he sent it if he hadn't received my money, but oh well. I was suddenly on the defensive about my purchase of this defective item, so I couldn't really complain about it until after he'd received my payment. Now I'm complaining about it.

Too damned complicated...