Amazon has the Amazon Basics Ergonomic 2.4 GHz Wireless Optical Mouse (G6B-BK) for $9.59 with free shipping for Prime members or on $35+. Features DPI adjustable, requires one AA battery (included).

Exclusively for Amazon Prime members. Amazon has the Amazon Basics Ergonomic 2.4 GHz Wireless Optical Mouse (G6B-BK, Black) for $9.59 with free shipping on $35+ or with Prime. List price: $13. Features 2.4 GHz wireless connection, requires one AA battery (included), DPI adjustable. Compatible with Windows 7, 8, and 10.

Has good Amazon Reviews.