Aliexpress
Click here… to search for MX3 Wireless Gyroscope Keyboard Air Mouse on Aliexpress
Here are coupons that you can use.
Latest coupon and price update (UTC):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
Coupon (19.22 USD): tRaDetRaCKeR
Coupon (19.22 USD): 8wEbgaInS5
Coupon (19.22 USD): pROMo8cuPoN
Coupon (19.43 USD): 2203ActiesNL
(CouponsFromChina.com tip: put item in your cart and apply coupon code there after clicking “Proceed to checkout”. Click to copy code and open shop)
Old coupons (from the oldest to the newest): 502C6B, PICODICOM, 13f142, 2020CNY, BGVDay10%off, aff7off, bGhOnEy10, BGdragonBoat, BGSS10%SW, bgshOOp10, BgoFErTaSchInA10, BGCuponation10, BANGGOODSD, 00c906, BGef96eb, Kortings10, 2022ACTIESNL, Terence, Tabby20, CouponsdePC
(sometimes old coupons work, so you can check them out (this site checks them on every price update))
Price history and price alert
Price history (for all/most countries) for MX3 Wireless Gyroscope Keyboard Air Mouse is here.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).