Well, even if you are giving the game away, do remember that you'll be sending it to Europe so it'll cost around 4 or 5$, I recommend that you at least ask the winner to pay you for the shipping.
As for me though, I don't have the game, but Mario Bros. ain't my thing so it's better to give it to someone else.
Also, for people saying that buying games outside their country is more expensive, a 3DS game in my country costs around 50€ so I buy them from Amazon.co.uk or Game.co.uk and get most games for roughly 35€, which is very cheap.