Aliexpress
Here are coupons that you can use.
Latest coupon and price update (UTC):
Banggood
Banggood warehouse is located in China. There is one coupon right now! Check this out.
Link: Banggood product page
Coupon (15.19 USD): BG589b2e
(CouponsFromChina.com tip: this code has to be applied 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): MVC8SPRING, tRaDetRaCKeR, pROMo8cuPoN, BGf94f14, BGLED2206, TTSUMMER8, Cuponation9, BGLED07
(I don’t think these’re gonna work, but you can try ’em out anyway)
Price history and price alert
Price history (for all/most countries) for 6W 220V COB LED Sewing Machine Working Light is here.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).