Canon offers its Canon X Mark I Slim Calculator/Mouse in Black (pictured) or White for $39.99. Coupon code "30CALC312" cuts it to $9.99. With $5.99 for shipping, that's $14 under our November mention and the lowest total price we could find by $9. This device connects via Bluetooth and serves as a wireless mouse, wireless keypad, and 10-digit calculator.

Canon also offers its Canon X Mark I Calculator Keypad in Black or White for $39.99. The above coupon code cuts it to $9.99. With $5.99 for shipping, that's the lowest total price we could find by $16. This device connects via Bluetooth and serves as a wireless keypad and 10-digit calculator.