Aliexpress
Here are coupons that you can use.
Latest coupon and price update (UTC):
Banggood
Banggood warehouse is located in China. You can get coupon down below.
Link: Banggood product page
Coupon (148.11 USD): BGNEWYEAR8
(CouponsFromChina.com tip: coupon code has to be applied in shop’s 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): BGAudio3, BGAUGUST8, BGAudio9, BGBFDAY8
(you can check these old coupons out, but these probably won’t work)
Price history and price alert
Price history (for all/most countries) for Xiaomi Sound Move Speaker BT5.3 Speaker HARMAN AudioEFX is here.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).