Just check coupons out (with price alert and history). Let’s see what best price is ATM.
Unit Diameter φ40mm*2, Microphone Yes, Frequency Response 180-20kHz, Output Power 5W*2, SNR 92dB, Impedance 40Ω, Transmission Distance 10m, Battery Capacity 2000mAh, Bluetooth Version V4.2, Working Time 15h, Connectivity Bluetooth/ Aux-in
Aliexpress
There’re some similar (or not) items on Aliexpress
Click here to search by yourself. 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
1. ($27.22): AFfbG10
put item in your cart and apply coupon code there after clicking “Proceed to checkout”. Click to copy code and open shop.
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/5cd
Old coupons (from the oldest to the newest): 502C6B, TTxBG10, BG3CSUM
(these codes were not working in latest coupon update, but you can check them out anyway)
Price history and price alert
Here is price history (for all/most countries) for Bakeey Waterproof 10W Bluetooth Speaker.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood and Aliexpress (only if product name will be the same as on Banggood and I will post it on social media though, so it’s more like Banggood price alert)).