Aliexpress
Click here… to search for DANIU Electric Energy Saving Power Meter 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 available! Pretty cool, huh?
Link: Banggood product page
Coupon (15.86 USD): AFfbG10
(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): c2b135
(these coupons are old, so probably won’t work)
Price history and price alert
Price history (for all/most countries) for DANIU Electric Energy Saving Power Meter is here.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).