Aliexpress
Click here… to search for Teclast C20 Pro 20000mAh Power Bank [EU] on Aliexpress
Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in Europe 
. This is new product in my database, so I don’t know if this price is good. There is one great coupon!
Link: Banggood product page
Coupon (36.79 USD): BG8ReviTrage
(CouponsFromChina.com tip: apply code in your basket (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): BG721532, BG0fbaa4
(you can check these old coupons out, but these probably won’t work)
Price history and price alert
Price history is not available for this item (not enough database records)! The lowest price was 20.99 USD though.
You can set price alert (for Banggood).