Meritline offers the refurbished Logitech M187 Wireless Mini Mouse in Black for $11.99. Coupon code "MLCU23QN" cuts it to $8.99. With free shipping, that's the lowest total price we could find for a new unit by $7. It features a nano-receiver, 2-button design, and scroll wheel.
A 90-day warranty applies, although it's unclear who provides it.