Aliexpress
Here are coupons that you can use.
Latest coupon code price check (UTC time):
Banggood
Banggood warehouse is located in China. There are no coupons available at this moment in Banggood.
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): BG3901f1, BGd0b05d, BG2589f4, 00c906, BG00c906, ADMITAD2212, 2022ACTIESNL
(you can check these old coupons out, but these probably won’t work)
Price history and price alert
Here is price history (for all/most countries) for 400pcs 6cm Breadboard Jumper Cable Dupont Wire.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).