Aliexpress
Click here… to search for Xiaomi MDZ-ZB-DE AI Portable Bluetooth Speaker on Aliexpress
Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in China. Well, there is one coupon available right now.
Link: Banggood product page
Coupon (25.40 USD): BGBuscape01
(CouponsFromChina.com tip: you should apply the coupon 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): fba5dc, e19855, c81c41, 60bb88, 55XMBT, TTxBG10, 25XMS, BGXM158, aff7off, BG3CSUM, BGIN58, bgssaff9, BG10AIRXM, AFfbG10, affbg10, 502C6B, BGBINKUPON158, BGCNXM7, BGXMAI99, 0e7f33, EARSP11, FBCOUPON1, BGLOAC1, 13f142, 451feb
(system checks these coupons on every price check (like once per 24 hours), but you can check them out anyway)
Price history and price alert
Here is price history (for all/most countries) for Xiaomi MDZ-ZB-DE AI Portable Bluetooth Speaker.
Price records source(s): Gearbest, Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).