Aliexpress
Here are coupons that you can use.
Other warehouses/versions
This item is available in 3 another warehouse/versions!
1. China – Yeelight YLKG13YL Double Wireless Smart Switch (-3 USD)
2. China – Yeelight YLKG14YL Triple Wireless Smart Switch (-3 USD)
3. Europe – Yeelight YLKG13YL Double Wireless Smart Switch [EU] (-3 USD)
Latest coupon code price check (UTC time):
Banggood
Banggood warehouse is located in China. I don’t think there is an active coupon right now – at least in my database.
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): BGYEE11COU, BGYLKG12YL, bgnewleds, BGLIGHT2020, BGYEBWCN, BGdragonBoat, bGhOnEy10, BGAFF10OFF, bgshOOp10, BGYEE20COUPON, BGLIGHT0920, BgoFErTaSchInA10, BGELIG0920, BgcLuBofErtA10, BGYEE2021, BGYEEL10, BGHONEY2110, BG10OFFAFF, BGwhielabel, BGLIG12, BG10OFFAFF1, BGYEELIGHT21, 00c906, BG00c906, ADMITAD2212, 2022ACTIESNL, Terence, BGLED2203
(probably won’t work, but you can try them out)
Other warehouses/versions
This item is available in 3 another warehouse/versions!
1. China – Yeelight YLKG13YL Double Wireless Smart Switch (-3 USD)
2. China – Yeelight YLKG14YL Triple Wireless Smart Switch (-3 USD)
3. Europe – Yeelight YLKG13YL Double Wireless Smart Switch [EU] (-3 USD)
Price history and price alert
Check out price history chart (for all/most countries) for Yeelight YLKG12YL Single Wireless Smart Switch.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).