#Nintendo seems is giving away a free game with the purchase of Mario Kart 8...
Honestly speaking if you own a Nintendo Wii U there shouldn't need to be an incentive to purchase Mario Kart 8 as in its a must have game. Nintendo is going after the crowd who doesn't already own a Wii U and offering them some of the best games for the console for free.
Super Mario Bros. U
The Legend of Zelda: Wind Waker HD
Wii Party U
Mario Kart 8 is Schedule to release on May 30, 2014
*Note you will have to register your Mario Kart 8 w/ Club Nintendo to receive you downloadable version of a game listed above*