I already own the demo, it cost me 45 euro and plays on my 3DS.
Where?
You can buy the 3DS version for around €10 now, if you want to give the game a try I highly recommend buying it on 3DS. It's a good game, especially online.
The console version will be a far better experience in my opinion. I played the 3DS demo and the console didn't do the game justice so I never bought the game. I'm far more likely to buy it on a home console.