SONOFF M5 80 SwitchMan Smart Wall Switch (Banggood, Aliexpress: SONOFF M5 80 SwitchMan Smart Wall Switch APP Control Work with Alexa Google Home and Siri shortcut – 2 Gang (the best price with coupon)).
Basically copy coupon, view price history or create e-mail price alert. Best price?
Aliexpress
There’re some similar (or not) items on Aliexpress
You can use link bot to get even lower price:
Click here to search by yourself. Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in China. I have no active coupons for you right now.
Link: Banggood product page
Price: $-3
It looks like this item is out of stock in Banggood. If you found it then please send me the link. I will replace it.
Click here to search on Banggood!
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/feV
Old coupons (from the oldest to the newest): BG58024b, Cuponation9, BGsonoff30, BG8ReviTrage, BGa16d12
(probably won’t work, but you can try them out)
Price history and price alert
Here is price history (for all/most countries) for SONOFF M5 80 SwitchMan Smart Wall Switch. The lowest price was: $12.99.
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)).