Aliexpress
Here are coupons that you can use.
Latest coupon code price check (UTC time):
Banggood
Banggood warehouse is located in China. One coupon is available. Cool!
Link: Banggood product page
Coupon (87.29 USD): BGGines
(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): Tabby20
(there’s a little possibility that old coupon will work)
Price history and price alert
Price history (for all/most countries) for OWON WIFI Tuya Single/3-phase Power Clamp is here.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).