$12.59 – ZK-MT21 bluetooth 5.0 Subwoofer Amplifier Board 50WX2+100W 2.1 Channel Power Audio Stereo Amplifier Tone Board Bass AMP AUX.
ZK-MT21 Bluetooth 5.0 Subwoofer Amplifier Board is for $12.59 (in Banggood). Basically copy coupon, view price history or create e-mail price alert. You probably want to know what is the best price?
Latest price update (UTC time):
Banggood ($12.59)
Banggood warehouse is located in China. So I have checked for active coupons (all category coupons and old ones), but there was no working coupon in Banggood. What about the price? Well, this price is higher than average price ($11.57)
Link: Banggood product page
Price: $12.59
Additional Banggood coupons: first page and second page
Old coupons (from the oldest to the newest): BG589b2e
(these codes were not working in latest coupon update, but you can check them out anyway)
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.
Price history and price alert
Here is price history (for all/most countries) for ZK-MT21 Bluetooth 5.0 Subwoofer Amplifier Board. The lowest price was: $10.99.
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)).