You can create price alert here, copy coupons and view price history. Best price?
Aliexpress
There’re some similar (or not) items on Aliexpress
Click here to search by yourself. Here are coupons that you can use.
Latest coupon code price check (UTC time):
Anti-Pollution PM2.5 Rechargeable Breathable Half Cover Face Guard for Open-air Activities
Banggood
Banggood warehouse is located in China. There is one coupon right now! Check this out.
Link: Banggood product page
1. ($34.10): AFfbG10
just apply this code in your cart after clicking “Proceed to checkout”. Click to copy code and open shop.
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/5cd
Old coupons (from the oldest to the newest): 935bc1
(probably won’t work, but you can try them out)
Price history and price alert
Price history (for all/most countries) for Xiaomi Purely Filter Mask Black is here.
Price records source(s): Gearbest, 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)).