Material Stainless Steel, Color Black + Silver, Size 3.8x 8.5x 20cm, Weight 250g, Model ML-KS2.
Just check coupons out (with price alert and history). Best price?
Aliexpress
There’re some similar (or not) items on Aliexpress
You can use link bot to get even lower price:
Click here to search by yourself. Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
1. ($11.47): BG3Q5
2. ($12.15): bGhOnEy10
put item in your cart and apply coupon code there after clicking “Proceed to checkout”. Click to copy code and open shop.
Additional Banggood coupons: first page and second page
Old coupons (from the oldest to the newest): BGMLKS2, TTxBG10, bgssaff9, AFfbG10, BGBFAFF2019, BGCITYADS2019, BGminleaf, BG322e14
(probably won’t work, but you can try them out)
Price history and price alert
Check out price history chart (for all/most countries) for Minleaf ML-KS2 4 In 1 Sharpener. The lowest price was: $9.22.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood and Aliexpress (only if product name will be the same as on Banggood and I will post it on social media though, so it’s more like Banggood price alert)).