Aliexpress
Click here… to search for 10Pcs N50 20x10x2mm Neodymium Block Magnet [EU] on Aliexpress
Here are coupons that you can use.
Latest coupon and price update (UTC):
Banggood
Banggood warehouse is located in Europe 
. Sorry, but there’s no price history in my database. Well, there is one coupon available right now.
Link: Banggood product page
Coupon (3.95 USD): BGAFF10OFF
(CouponsFromChina.com tip: just apply this code 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): bGhOnEy10, BGdragonBoat, BgcLuBofErtA10
(you can check these old coupons out, but these probably won’t work)
Price history and price alert
Well, you won’t see price history chart, coz we have only 1 database record for this item (and price was 3.6 USD).
You can set price alert (for Banggood).