Aliexpress
Click here… to search for Xiaomi VIOMI VF1500 Vacuum Flask on Aliexpress
Here are coupons that you can use.
Latest coupon and price update (UTC):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
Coupon (49.54 USD): bGhOnEy10
Coupon (49.54 USD): BGdragonBoat
Coupon (49.54 USD): BGAFF10OFF
Coupon (49.54 USD): BGHOMEA15%
Coupon (49.54 USD): BgcLuBofErtA10
(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): AFfbG10, BGGR377, BGBTV29, BGBFAFF2019, BGCITYADS2019, BGVDay10%off, BGHOMEG12, BGMPB2020, BGSS10%SW, bgshOOp10, BGHome15%
(sometimes old coupons work, so you can check them out (this site checks them on every price update))
Price history and price alert
Check out price history chart (for all/most countries) for Xiaomi VIOMI VF1500 Vacuum Flask.
Price records source(s): Gearbest, Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).