Aliexpress
Here are coupons that you can use.
Latest coupon code price check (UTC time):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
Coupon (264.15 USD): Email5
Coupon (264.15 USD): BG3DP09B
(CouponsFromChina.com tip: put item in your cart and apply coupon code there 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): 661c93, Wholesale20
(probably won’t work, but you can try them out)
Price history and price alert
Here is price history (for all/most countries) for ZONESTAR Z5M2 3D Printer EU Plug.
Price records source(s): Gearbest, Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).