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 (30.05 USD): BGOL786
Coupon (31.81 USD): AFfbG10
Coupon (32.88 USD): aff7off
(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): 502C6B, e2bcea, TTxBG10, BGOD1, BGBFAFF2019, BGCITYADS2019
(these coupons are old, so probably won’t work)
Price history and price alert
Do you need price history chart (for all/most countries) for Xiaomi Youpin 90 FUN Portable Backpack Black? There we go.
Price records source(s): Gearbest, Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).