Aliexpress
Click here… to search for AC-MTB-01N 17.5Ah 48V 750W Electric Bicycle [EU] on Aliexpress
Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in Europe 
. I don’t want to misguide you about the price. I don’t know if it’s good, because I don’t have enough records in my database… I found coupon for you. Check this out.
Link: Banggood product page
Coupon (3059.99 USD): eridingSeps
(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): BG5ebc6b, BG11fc93, BG2e041f, 341d2f, BG061584, BG589b2e, BGAUGUST8
(sometimes old coupons work, so you can check them out (this site checks them on every price update))
Price history and price alert
There is only one database record (it was for 2598.62 USD), so you can’t see price history chart.
You can set price alert (for Banggood).