B&H Photo-Video offers the Wacom Bamboo Stylus Duo / Pen, model no. CS110K, for $5.95 with free shipping. That's the lowest total price we could find by $14. It features a 9mm tip and is compatible with most mobile devices. It includes a refillable ink barrel for taking notes on paper.
Need it in time for Christmas? Order by December 19 at 4 pm ET via two-day shipping for $12.94.