According to my DB the lowest price is $21.99 for WIFI Digital Wattmeter EU Plug 220V (in Banggood). Just check coupons out (with price alert and history). What is best price?
Latest coupon code price check (UTC time):
Weight: 160g, Working humidity: <80%, Power: MAX3680W, Accuracy: +1%, Wi-Fi frequency: 2.412 ~ 2.484 MHz, Dimensions: 133X76X73mm, Measuring voltage: AC85-265V, Date function: month/day, frequency: 50 / 60HZ, Material: ABS + PC, Type: Wifi version /Bluetooth version (optional), Plug type: EU plug, Energy Measurement range: 0 ~ 1999kWh, Power factor: 0-1.00PF, Measuring current: 0-16A Max16A, Working temperature: -10°C ~ +60°C degree, Security Type: WEP64 / WEP128 / TKIP / CCMP (AES), Wireless consumption: <0.3W, Model: S1W, Screen Type: 2.4inch TFT-LCD HD Display Panel Graphic 240´RGB´320 Dot-matrix
Banggood ($21.99)
Banggood warehouse is located in China. So I have checked for active coupons (all category coupons and old ones), but there was no working coupon in Banggood. Is it expensive? Hmmm, price is higher than average (which is $19.99 right now), so better set price alert down below…
Link: Banggood product page
Price: $21.99
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/5cd
Old coupons (from the oldest to the newest): BGGines, BG0dd754, BGTOOS729
(there’s a little possibility that old coupon will work)
Aliexpress
There’re some similar (or not) items on Aliexpress
Click here to search by yourself. Here are coupons that you can use.
Price history and price alert
Check out price history chart (for all/most countries) for WIFI Digital Wattmeter EU Plug 220V.
Price records source(s): Banggood
Click on image to enlarge. 
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)).