I don't think Riku is doing anything wrong at all to be honest, as OL said , it's just a video game, if someone wants to pay over the odds for it, then that's fair game. I also see where SC is coming from too though, if someone is buying entire stocks of the game and making it nearly impossible for others to buy it just so they can sell them all at a higher price, then yeah that's very shystie (and so are those fools who "phantom" buy stuff on ebay to deliberately raise the value of certain items). But anyone who really wanted Ni No Kuni Wizard Edition at the normal price had more than enough opportunity, so as I said, if they're now willing to pay more for a fancy edition of a game (and clearly have more disposable income then me!), I'd let them.
I've done the same thing in the past. I was in a shop once, and saw two copies of MGS subsistence being sold for £15. I bought both and stuck one of them on ebay straight away for £45 (undercutting the other sellers), and it sold within minutes. Did I feel guilty? Not at all.
Riku just made a good investment, it's that simple. Sure, I'd gain respect for you if you gave it away the game for free, but I wouldn't lose respect for you if you didn't, we live in a capitalist society not a buddhist monastry, and have to play by the rules to an extent. Riku isn't being dishonest and that's the main thing to me.
All this talk of "morals" is getting way off the subject, and a it's a very contentious subject itself. Are we naturally "moral", is it human nature? It can be argued either way, but you only need to look at the different societies or different time periods to see how variable morality can be.