Newegg has the Energy Power12 Sub 12" 150W Front-Firing Rear Ported Subwoofer (Black) on sale for $149.99 + $10 Newegg Gift Card. Shipping is free.
Specs:
12" front-firing woofer
Rear slot port
Line level and speaker level inputs
Volume control, crossover control, phase switch and power switch on amp panel
https://www.newegg.com/p/0S6-001B…001B-00008