Just check coupons out (with price alert and history). Do you want to know what the best price is?
Max use distance 10m / 3.94inch, braid belt, Weight 50g, Charging interface USB standard interface, gold plated electrode, sponge, Support system bluetooth 4.0 or above, Brand Xiaomi, Charging time 2 hours, Material EVA composite imitation, Battery capacity 55mAh
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):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
1. ($60.46): BGAFF10OFF
2. ($60.46): bGhOnEy10
3. ($62.18): Email3
put item in your cart and apply coupon code there 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): BGkonimbesinEYE, BGOD1, AFfbG10, affbg10, BGtravel305, BGBFAFF2019, BGCITYADS2019, BGTS204, BGMPB2020
(there’s a little possibility that old coupon will work)
Price history and price alert
Do you need price history chart (for all/most countries) for Xiaomi Air Sleeping Eye Mask? There we go.
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)).