Aliexpress
Click here… to search for Xiaomi Yeelight Mosquito Swatter Killer Lamp on 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 (36.62 USD): BG10OFFAFF1
(CouponsFromChina.com tip: 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
Old coupons (from the oldest to the newest): BGYEELIGHT88, BGYEELIGHT5555, TTxBG10, BGHealth2, ML15%Pro, vipupgrade8, BGYeelight6, AFfbG10, BGYEE11COU, bGpAnDacHeCk, 2020CNY, BGbeauty001, bgshOOp10, BGHB20, BgoFErTaSchInA10, BGYEE20COUPON, BGSD52147, BgcLuBofErtA10, BGYEE2021, BGCuponation10, BGYEEL10, BG10OFFAFF, BGwhielabel, BGLIG12
(you can check these old coupons out, but these probably won’t work)
Price history and price alert
Check out price history chart (for all/most countries) for Xiaomi Yeelight Mosquito Swatter Killer Lamp.
Price records source(s): Gearbest, Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).