$23.99 – SONOFF M5 86 SwitchMan Smart Wall Switch (Banggood, Aliexpress: 1x M5 86 SwitchMan Smart Wall Switch, 2x Screw, 1x User Manual (the best price with coupon)).
You can get SONOFF M5 86 SwitchMan Smart Wall Switch for $23.99 with coupon (from Banggood). Price history, coupons and price alert are available on this page. What is best price?
Latest coupon code price check (UTC time):
Banggood ($23.99)
Banggood warehouse is located in China. I have no active coupons for you right now. Is it good price? Maybe there’re no more promotions for this item, because current price is higher than average (which is equal $19.29)
Link: Banggood product page
Price: $23.99
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/feV
Old coupons (from the oldest to the newest): pROMo8cuPoN, BG15Sonoff, BG8ReviTrage, Cuponation9, 9OFFSUMMER, BG1a25ab, BGsonoff30, BGb537ba, BG57731d
(there’s a little possibility that old coupon will work)
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.
Price history and price alert
Here is price history (for all/most countries) for SONOFF M5 86 SwitchMan Smart Wall Switch. The lowest price was: $12.79.
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)).