Aliexpress
Here are coupons that you can use.
Other warehouses/versions
This item is available in 1 another warehouse/version!
1. Europe – 2Pcs SONOFF Two Way Smart Switch 10A [EU] (-3 USD)
Latest price update (UTC time):
Banggood
Banggood warehouse is located in China. I have no active coupons for you right now.
Link: Banggood product page
Price: -3 USD
It looks like this item is out of stock in Banggood. If you found it then please send me the link. I will replace it.
Click here to search on Banggood!
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:
Old coupons (from the oldest to the newest): BG2MINI, BGSFMINI, elec, SONOFF15, BGBFCR31, 13f142, BGVDay10%off, BGTT10, bGhOnEy10, BGSMOFF, bgshOOp10, BGSAMRTH, BGELIG0920, BgcLuBofErtA10, BGSONOFF16, BGAFF10OFF, BGSTHO15, BGCuponation10, BGHONEY2110, BGSHOM15, BGSHE15, 6GSGIT, ADMITAD2212, BGSmart6, 8BGwbg2204, 2203ActiesNL, tRaDetRaCKeR, 8wEbgaInS5, pROMo8cuPoN, BG15Sonoff, Cuponation9, BG8ReviTrage
(these codes were not working in latest coupon update, but you can check them out anyway)
Other warehouses/versions
This item is available in 1 another warehouse/version!
1. Europe – 2Pcs SONOFF Two Way Smart Switch 10A [EU] (-3 USD)
Price history and price alert
Check out price history chart (for all/most countries) for 2Pcs SONOFF Two Way Smart Switch 10A.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).