$9.99 – Voice Control: Compatible with Alexa Google Home, Operation Humidity: ≤90%, Rated Voltage: 100~240V 50/60Hz, Shell Material: PC/Flammability Rating: V0, Operation Temperature: -10~40℃, Rated Current: 10A, App: TuyaSmart/Smart Life, Physical Two-way Control: Support, Size: 39.2*39.2*18mm, WiFi Standard: IEEE 802.11 b/g/n 2.4Ghz Only.
ATM you can buy Tuya WiFi Smart Switch Module 1 Gang for $9.99 (in Banggood). Just check coupons out (with price alert and history). Best price?
Latest price update (UTC time):
Banggood ($9.99)
Banggood warehouse is located in China. There are no coupons for this product in Banggood. The question is – is it a good price? Hmmm, price is higher than average (which is $9.54 right now), so better set price alert down below…
Link: Banggood product page
Price: $9.99
Additional Banggood coupons: first page and second page
Old coupons (from the oldest to the newest): BG1534df, BG7fbb5b
(I don’t think these’re gonna work, but you can try ’em out anyway)
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
Do you need price history chart (for all/most countries) for Tuya WiFi Smart Switch Module 1 Gang? There we go. The lowest price was: $7.19.
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)).