Aliexpress
Click here… to search for Joyroom UM2 EU Charger on Aliexpress
Here are coupons that you can use.
Latest coupon and price update (UTC):
Banggood
Banggood warehouse is located in China. Only one coupon available!
Link: Banggood product page
Coupon (8.35 USD): BG00c906
(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): TTxBG10, aff7off, BG3CSUM, bgssaff9, AFfbG10, BGBAK15, bGhOnEy10, BGXMI15, BGdragonBoat, BGSS10%SW, BGAFF10OFF, BgoFErTaSchInA10, BgcLuBofErtA10, BG20CHARGER, BGMBCBLE, BGHONEY2110, 13f142, BANGGOODSD, BG85d5c6
(these codes were not working in latest coupon update, but you can check them out anyway)
Price history and price alert
Price history (for all/most countries) for Joyroom UM2 EU Charger is here.
Price records source(s): Gearbest, Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).