Aliexpress
Here are coupons that you can use.
Other warehouses/versions
This item is available in 1 another warehouse/version!
1. Europe – SONOFF POW R2 WiFi Smart Light Switch [EU/UK] (-3 USD)
Latest coupon code price check (UTC time):
Banggood
Banggood warehouse is located in China. There is one coupon right now! Check this out.
Link: Banggood product page
Coupon (20.39 USD): Couponsde7
(CouponsFromChina.com tip: apply it in your cart after clicking “Proceed to checkout”. Click to copy code and open shop)
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k
Old coupons (from the oldest to the newest): elec, 502C6B, e2bcea, BGpowr2, SONOFF15, BGVDay10%off, BGMPB2020, bGhOnEy10, BGSMOFF, 13f142, BGSONOFF15, BGELIG0920, BgcLuBofErtA10, BGSONOFF16, BGAFF10OFF, BGSTHO15, BGCuponation10, BGHONEY2110, BGSHOM15, BGSHE15, 6GSGIT, BG15Sonoff
(system checks these coupons on every price check (like once per 24 hours), but you can check them out anyway)
Other warehouses/versions
This item is available in 1 another warehouse/version!
1. Europe – SONOFF POW R2 WiFi Smart Light Switch [EU/UK] (-3 USD)
Price history and price alert
Check out price history chart (for all/most countries) for SONOFF POW R2 WiFi Smart Light Switch.
Price records source(s): Gearbest, Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).