Aliexpress
Here are coupons that you can use.
Latest coupon and price update (UTC):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
Coupon (18.29 USD): BGLED2203
Coupon (19.33 USD): Terence
Coupon (19.53 USD): BG00c906
(CouponsFromChina.com tip: coupon code has to be applied in shop’s 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): BGYEE2021, BGYEEL10, BGWEYK247, BGHONEY2110, BG10OFFAFF, BGRYLDP004, BGJDER124, BGwhielabel, BGDHF2314, BGSDM21, BG2ac927, BGa5ab5b, BGDKF2134, BGebd713, BGDFJQM3, BGLIG12, BG10OFFAFF1, 00c906, BG91f32a, ADMITAD2212, 2022ACTIESNL
(these coupons are old, so probably won’t work)
Price history and price alert
Price history (for all/most countries) for YEELIGHT YLDP004 4.8W GU10 2700K Dimming Smart LED Bulb is here.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).