Amazon offers Prime members the Ten One Design Pogo Connect Bluetooth Smart Pen for iPad, model no. T1-PGCT-302, for $10.13 with free shipping. (Non-members can spend $35 to qualify for free shipping; otherwise, it adds $8.06.) That's the lowest total price we could find by $70. Features include 0-gram activation, location beacon, and compatibility with iPad 3 and 4.

Update: The price has dropped to $9.95.