You can create price alert here, copy coupons and view price history. What is the best price?
Aliexpress
There’re some similar (or not) items on Aliexpress
Click here to search by yourself. Here are coupons that you can use.
Latest coupon and price update (UTC):
Dimensions type: 478x 478x 670mm, Rated current: 10A, Net weight: 68.4g, Plug type: EU plug, Housing material: PC/ABS, Wireless type: WiFi 2.4GHz b/g/n, APP Name: eWeLink, Rated power: 90V~250V AC
Banggood
Banggood warehouse is located in Europe 
. This is new product in my database, so I don’t know if this price is good. Well, there is one coupon available right now.
Link: Banggood product page
1. ($11.04): BGSmart6
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 and https://couponsfromchina.com/short/5cd
Price history and price alert
It doesn’t make sense to generate price history chart, because there is one price record which is: $11.04.
You can set price alert (for Banggood and Aliexpress (only if product name will be the same as on Banggood and I will post it on social media though, so it’s more like Banggood price alert)).