Aliexpress
Click here… to search for Xiaomi Zanjia 2L Water Bottle on Aliexpress
Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
Coupon (50.39 USD): BGTY704CP
Coupon (50.39 USD): BGAFF10OFF
(CouponsFromChina.com tip: apply it 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): 7d18f7, bGhOnEy10, BGdragonBoat, BGCAMP01, bgshOOp10, BgoFErTaSchInA10, BgcLuBofErtA10, BGZPBC15
(these coupons are old, so probably won’t work)
Price history and price alert
Price history (for all/most countries) for Xiaomi Zanjia 2L Water Bottle is here.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).