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 (27.22 USD): AFfbG10
(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): 502C6B, TTxBG10, BG3CSUM
(I don’t think these’re gonna work, but you can try ’em out anyway)
Price history and price alert
Do you need price history chart (for all/most countries) for Bakeey Waterproof 10W Bluetooth Speaker? There we go.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).