Why do you say it's Morally wrong? I'm not saying I disagree, I'm interested in your reasoning.
Buying something cheap and selling it as an intermediary for profit is at the basic level what retailers do to us, but people don't accuse Argos or Debenhams of being immoral.
The difference between retailers and members of the public in this example, is that retailers make their profit, by buying massive quanities of stock in bulk at a lower price than Apple's recommended retail price.
The retailer then sells the item at the same price the Manufacturer would. That's basic retailing theory, and nothing too immoral.
If a member of the public buys the same item from a retailer at RRP, with the intention of selling it on at an exploitatively higher price, that's immoral in my opinion. It's unreasonable personal gain versus the needs of others as I see it.
Obviously lots of people disagree with me, as there are hundreds doing this sort of thing on ebay.