Impedance: 4-8 ohm, Color: Black, Audio Encoding: Mono, Material: Aluminum Alloy Panel, Gross Weight: 641g, Voltage: DC 12V, Max Power: 600W, Size: 170x145mm.
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.
Updated:
Banggood
Warehouse in Europe 
.
Link: 12V 600W Car Audio Subwoofer Amplifier Board [EU]
$26.34 with coupon: BGLMQ15
$27.27 with coupon: BGSCM11
Additional Banggood coupons:
1. First page
2. Second page
Price history and price alert
We don’t have enough records in database to show price history for this item. BTW: We have only recorded this price: $25.19.
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)).