Newegg offers the refurbished Logitech M560 Wireless Mouse in Silver, model no. 910-003910, for $9.99 with free shipping. That's tied with our March mention as the lowest total price we've seen. (It's a current low for a new unit by $11.) This wireless mouse features a USB nano-receiver, Windows 8 edge menu button, and ambidextrous design. One AA battery is required (included).
A 90-day warranty is included, but it's unclear who backs it.