With designer leather goods its hard to tell from pictures alone. Though the stitching can reveal a lot, it's all about the feel and sturdy-ness of the product. I do know for sure Prada ships their leather goods and accessories in those purple boxes. Inside that envelope should be a magnetic strip card used for the manufacture to identify the item incase it gets RTV'd because of a defect.
All the nessessary extras are there. The best way to tell real wallets is to feel them. I'm kind of iffy about this one because the stitching on the top lip of the wallet is not consistent. There is a bit more leather on the ends of the wallet, then its kind of goes lopsided as it nears the middle.
Your best bet it to purchase it at the 35.00 and see if its real.. feel it. If not the listing says its returnable.
Oh, and the 35.00 BIN .. this is really really low for an authentic Prada from 2006. I've seen womens wallets on sale from previous collections +6 months old at outlets for 175-209.99. So Its hard to tell how he/she got it at such a LOW price.