Aliexpress
Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in China. There is one coupon right now! Check this out.
Link: Banggood product page
Coupon (11.99 USD): 13f142
(CouponsFromChina.com tip: you should apply the coupon in your 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): BGPEH790, TTxBG10, aff7off, bgssaff9, AFfbG10, BGPET30Cokit, 502C6B, BGBFAFF2019, BGCITYADS2019, BGVDay10%off, BGHOMEG12, BGAFF10OFF, bGhOnEy10, BGJJCWJP, BGHome15%, BgcLuBofErtA10, BGHONEY2110
(these coupons are old, so probably won’t work)
Price history and price alert
Do you need price history chart (for all/most countries) for Xiaomi Pet External Insect Repellent Ring? There we go.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).