Aliexpress
Click here… to search for Minleaf ML-KS2 4 In 1 Sharpener on Aliexpress
Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
Coupon (11.47 USD): BG3Q5
Coupon (12.15 USD): bGhOnEy10
(CouponsFromChina.com tip: paste coupon code in your cart and click Apply after clicking “Proceed to checkout”. Click to copy code and open shop)
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k
Old coupons (from the oldest to the newest): BGMLKS2, TTxBG10, bgssaff9, AFfbG10, BGBFAFF2019, BGCITYADS2019, BGminleaf, BG322e14
(there’s a little possibility that old coupon will work)
Price history and price alert
Price history (for all/most countries) for Minleaf ML-KS2 4 In 1 Sharpener is here.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).