Aliexpress
Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in China. There is one great coupon!
Link: Banggood product page
Coupon (11.30 USD): BGc4a05f
(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): BG32e48e, BG23ALEAprD, BG081591
(you can check these old coupons out, but these probably won’t work)
Price history and price alert
Here is price history (for all/most countries) for Indoor Home Room LED UV Mosquito Killing Lamp.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).