In the US, the Sensei sells for $16 (or 16 times the price of a copy of Fruit Ninja), the Watermelon for $15 (1.5 Fruit Ninja Kinects), and a "Training Pack" of both for $30. The Sensei is available now, but that adorable melon is shipping in mid-January.
We may sound as if we're giving Halfbrick a hard time for cashing in on Fruit Ninja, but we're happy for the developer. The games have been universally worthwhile, and the toys are undeniably huggable. Besides, Halfbrick has to raise money to save the Australian game industry, pretty much single-handed.