1x Relay module.
Just check coupons out (with price alert and history). What is the best price?
Aliexpress
There’re some similar (or not) items on Aliexpress
You can use link bot to get even lower price:
| Image | Product (link) | Price | Coupons |
|---|---|---|---|
 |
ESP8266 ESP-01 5V 12V 1 2 4 Way WiFi Relay Module Things Smart Home Remote Control Switch 1Channel/2Channel/4Channel WIFI Relays | $3.93 | – |
Click here to search by yourself. Here are coupons that you can use.
Latest coupon and price update (UTC):
Banggood
Banggood warehouse is located in China. One coupon is available. Cool!
Link: Banggood product page
1. ($9.39): BG00c906
put item in your cart and apply coupon code there after clicking “Proceed to checkout”. Click to copy code and open shop.
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/i1u
Old coupons (from the oldest to the newest): 2203ActiesNL, BGJUNEGSG9, Cuponation9
(you can check these old coupons out, but these probably won’t work)
Price history and price alert
Do you need price history chart (for all/most countries) for 5V/12V ESP8266 4 Channels WiFi Relay? There we go. The lowest price was: $9.09.
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)).