The promotion runs until Saturday 31st December 2016, and will allow those that purchase the Wii U exclusive to receive the Mario, Luigi, Peach, Yoshi, Bowser or Toad amiibo entirely free of charge, as well as the branded tennis ball that is usually up for grabs.
In order to claim your prize, all you need to do is use the related amiibo promotion code at the checkout after which it will be added to your basket:
Mario amiibo: MARIOAMIIBO
Luigi amiibo: LUIGIAMIIBO
Peach amiibo: PEACHAMIIBO
Yoshi amiibo: YOSHIAMIIBO
Bowser amiibo: BOWSERAMIIBO
Toad amiibo: TOADAMIIBO
This promotion can only be used with a packaged copy, meaning that it won’t apply to a digital copy, and it is limited to one promotion code per transaction.
When scanned in Mario Tennis: Ultra Smash, the amiibo character can play alongside you in Knockout mode where they can be trained to unlock special perks.