Aliexpress
Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
Coupon (16.99 USD): BGGKKEL1
Coupon (17.99 USD): BGTT10
Coupon (17.99 USD): bGhOnEy10
(CouponsFromChina.com tip: 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
Old coupons (from the oldest to the newest): BGUF179, BGdragonBoat, bgshOOp10, BGHome15%
(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 Xiaowei X3Pro 240/330ml UV Soap Dispenser.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).