Aliexpress
Click here… to search for Xiaomi Outdoor Bluetooth 5.0 Speaker on Aliexpress
Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in China. There is one coupon available! Pretty cool, huh?
Link: Banggood product page
Coupon (53.99 USD): 13f142
(CouponsFromChina.com tip: apply it 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): BGXMS38, PICODICOM, BGXMOS, AFfbG10, 502C6B, BGOS22, BGMT1H, BGBFAFF2019, BGCITYADS2019, BGXMS055, EARSP11, BGXMBB3, BGAFF10OFF, bGhOnEy10, BGSS10%SW, bgshOOp10, 7d18f7, BGELIG0920, BG4BW25, BGLOAC1, 451feb
(these coupons are old, so probably won’t work)
Price history and price alert
Check out price history chart (for all/most countries) for Xiaomi Outdoor Bluetooth 5.0 Speaker.
Price records source(s): Gearbest, Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).