Aliexpress
Click here… to search for Xiaomi Mijia Smooth 0.5mm Pen WIth 3Pcs Black Ink Refill on Aliexpress
Here are coupons that you can use.
Other warehouses/versions
This item is available in 1 another warehouse/version!
1. Europe – Xiaomi Mijia Smooth 0.5mm Pen WIth 3Pcs Black Ink Refill [EU] (-3 USD)
Latest price update (UTC time):
Banggood
Banggood warehouse is located in China. Well, there is one coupon available right now.
Link: Banggood product page
Coupon (8.99 USD): BGAFF10OFF
(CouponsFromChina.com tip: apply code in your basket (cart) 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): MLPEN799, e2bcea, TTxBG10, ea5394, bgssaff9, AFfbG10, BGTT10, bGhOnEy10, BGdragonBoat, BGMS042, BGWE833, BgoFErTaSchInA10, BgcLuBofErtA10, 00c906
(you can check these old coupons out, but these probably won’t work)
Other warehouses/versions
This item is available in 1 another warehouse/version!
1. Europe – Xiaomi Mijia Smooth 0.5mm Pen WIth 3Pcs Black Ink Refill [EU] (-3 USD)
Price history and price alert
Here is price history (for all/most countries) for Xiaomi Mijia Smooth 0.5mm Pen WIth 3Pcs Black Ink Refill.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).