Amazon offers Prime members the Nintendo Wii U Fit Meter for $9.75 with free shipping. (Non-members can spend $35 to bag free shipping; otherwise, it adds $4.98.) Outside of the below mention, that's tied with our July mention and the lowest total price we could find by $4. It features a 3-axis accelerometer and measures the amount of steps you've taken plus the number of calories you've burned. The data collected can be transferred to the Wii U via the IR port on the gamepad.
A close price: Walmart offers it for $10 with free in-store pickup. Prime orders placed at Amazon by December 22 are guaranteed to arrive by Christmas.