compatible with USB1.1, Charging time: DC5V 1000mA and above USB power supply, Wireless connections: 50Hz ~ 20KHz, power supply: Built-in 18650 3.7V 4000mAh 3C battery, USB specification: Bluetooth 4.2, Output Power: 50x90mm Super-Bass, file format: USB2.0.
Just check coupons out (with price alert and history). What is the best price?
Aliexpress
There’re some similar (or not) items on Aliexpress
You can use link bot to get even lower price:
Click here to search by yourself. Here are coupons that you can use.
Latest coupon code price check (UTC time):
Banggood
Banggood warehouse is located in China. One coupon is available. Cool!
Link: Banggood product page
1. ($74.18): BGBuscape01
coupon code has to be applied in shop’s cart after clicking “Proceed to checkout”. Click to copy code and open shop.
Additional Banggood coupons: first page and second page
Old coupons (from the oldest to the newest): 1c9a82, 502C6B, TTxBG10, aff7off, BG3CSUM, AFfbG10, BGBFAFF2019, BGCITYADS2019, BGVDay10%off, EARSP11, BGAFF10OFF, bGhOnEy10, 7d18f7, BGSS10%SW, bgshOOp10, BGELIG0920, BG11PP7, Email5, BG4BW25, BGLOAC1, 13f142
(sometimes old coupons work, so you can check them out (this site checks them on every price update))
Price history and price alert
Price history (for all/most countries) for MIFA A20 30W Bluetooth Speaker Red is here. The lowest price was: $54.39.
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)).