Aliexpress
Here are coupons that you can use.
Other warehouses/versions
This item is available in 1 another warehouse/version!
1. China – Deerma WYD-Y1 Mosquito-Trap Agent (-3 USD)
Latest coupon and price update (UTC):
Banggood
Banggood warehouse is located in China. You can get coupon down below.
Link: Banggood product page
Coupon (21.25 USD): 502C6B
(CouponsFromChina.com tip: paste coupon code in your cart and click Apply 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): 8bc905, vipupgrade8, TTxBG10, aff7off
(these coupons are old, so probably won’t work)
Other warehouses/versions
This item is available in 1 another warehouse/version!
1. China – Deerma WYD-Y1 Mosquito-Trap Agent (-3 USD)
Price history and price alert
Check out price history chart (for all/most countries) for Xiaomi Deerma DEM-ZW100 Mosquito Dispeller.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).