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 (637.49 USD): BGLOAC1
Coupon (744.99 USD): 7d18f7
(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): BGLSUH, bGpAnDacHeCk, BGHOMEAPP, BGTT10, bGhOnEy10, BGMASXM, BGXMSL, 7bcdf9, BGSS10%SW, bgshOOp10, BGHome15%, BGHOMEAPP13, BGHOMEA13
(there’s a little possibility that old coupon will work)
Price history and price alert
Check out price history chart (for all/most countries) for Xiaomi MORROR ART Lyrics Bluetooth Speaker 40W.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).