Aliexpress
Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in China. There is one great coupon!
Link: Banggood product page
Coupon (37.14 USD): BGAudio3
(CouponsFromChina.com tip: just apply this code 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): BG73fade, BGAUDIO, BG9ba0e8, BG1b5830, BGXIFD186
(sometimes old coupons work, so you can check them out (this site checks them on every price update))
Price history and price alert
Here is price history (for all/most countries) for XDOBO Prince 1995 15W Bluetooth 5.0 Speaker.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).