Aliexpress
Here are coupons that you can use.
Other warehouses/versions
This item is available in 1 another warehouse/version!
1. Europe – SONOFF BASIC R3 10A 2200W Smart Switch [EU/UK] (-3 USD)
Latest price update (UTC time):
Banggood
Banggood warehouse is located in China. Only one coupon available!
Link: Banggood product page
Coupon (13.74 USD): BGSmart6
(CouponsFromChina.com tip: you should apply the coupon 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, BGbasicr3, SONOFF15, BGVDay10%off, bGhOnEy10, BGSMOFF, BGSONOFF15, BGELIG0920, 13f142, BgcLuBofErtA10, BGSONOFF16, BGAFF10OFF, BGSTHO15, BGCuponation10, BGHONEY2110, BGSHOM15, BGSHE15, BG9395a9, 6GSGIT, BG15Sonoff
(probably won’t work, but you can try them out)
Other warehouses/versions
This item is available in 1 another warehouse/version!
1. Europe – SONOFF BASIC R3 10A 2200W Smart Switch [EU/UK] (-3 USD)
Price history and price alert
Here is price history (for all/most countries) for SONOFF BASIC R3 10A 2200W Smart Switch.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).