Aliexpress
Click here… to search for Xiaomi NDZ-19-AI Bluetooth K-Song Headphones 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 (93.62 USD): Email5
Coupon (93.62 USD): BGSS10%SW
(CouponsFromChina.com tip: paste coupon code in your cart and click Apply after clicking “Proceed to checkout”. Click to copy code and open shop)
Old coupons (from the oldest to the newest): 10XMKPM, 502C6B, TTxBG10, 2019SPEDM, BG3CSUM, AFfbG10, affbg10, BGBFAFF2019, BGCITYADS2019, EARSP11, BGMPB2020, BGAFF10OFF, bGhOnEy10
(there’s a little possibility that old coupon will work)
Price history and price alert
Here is price history (for all/most countries) for Xiaomi NDZ-19-AI Bluetooth K-Song Headphones.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).