Aliexpress
Here are coupons that you can use.
Other warehouses/versions
This item is available in 1 another warehouse/version!
1. Europe – SONOFF PIR3-RF 433MHz RF PIR Motion Sensor [EU] (7.99 USD)
Latest coupon and price update (UTC):
Banggood
Banggood warehouse is located in China. Hmmm… There is no active coupon in Banggood at this moment.
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
Old coupons (from the oldest to the newest): BGSONOFF20, BGPIR3, 13f142, 6GSGIT, BGSmart6, MVC8SPRING, 8BGwbg2204, 2203ActiesNL, tRaDetRaCKeR, 8wEbgaInS5, pROMo8cuPoN, BGJUNEGSG9, BG15Sonoff, TTSUMMER8, Cuponation9, 9OFFSUMMER, BG6035ab, BG060319, BG56376f
(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 PIR3-RF 433MHz RF PIR Motion Sensor [EU] (7.99 USD)
Price history and price alert
Price history (for all/most countries) for SONOFF PIR3-RF 433MHz RF PIR Motion Sensor is here.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).