You can get R4 Wifi Switch for 10.99 USD using coupon code (in Banggood). Go down and check coupons out. Remember to check price history if it is available. You probably want to know what is the best price?
Latest price update (UTC time):
Banggood (10.99 USD)
Banggood warehouse is located in China. I’m afraid that there’s no working coupon in Banggood. Well, is it a good price anyway? This price is higher than average price (10.66 USD) for this item.
Link: Banggood product page
Price: 10.99 USD
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k
There were country-specific coupon codes published on Couponsfromchina social channels and price alerts. Coupon price may vary by country, because there’re different VAT rates, shipping cost etc. There is a chance that some latest coupons are still working:
Coupon (8.4.2024, $10.49): BGc340e9
Item: SONOFF MINI R4 Wifi Switch Module
Countries: Greece
Coupon (7.4.2024, $10.49): BG0ded01
Item: SONOFF MINI R4 Wifi Switch Module
Countries: CzechRepublic, Hungary, Portugal, Slovakia(SlovakRepublic), Slovenia, Spain
Coupon (4.4.2024, $10.49): BG856c53
Item: SONOFF MINI R4 Wifi Switch Module
Countries: France, Italy
Aliexpress
Click here… to search for SONOFF MINI R4 Wifi Switch Module on Aliexpress
Here are coupons that you can use.
Price history and price alert
Here is price history (for all/most countries) for SONOFF MINI R4 Wifi Switch Module.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).