This is a good deal.
Diy Mobile Audio - Pioneer Premier PRS-x320 $175 BNIB

 

The sub you listed is DVC 4 ohm. Parallel, that gives you a 2 ohm load.
So, you need a mono amp around 500 W.
The stereo amp you listed could only do 2 x 200 at 4 ohm, so i guess you could use it with one output on each coil. but thats not ideal.
But, if its free?

 

It's a single 4ohm voice coil driver.

 

OK, If you say so. So, how come the spec sheet says dual?
Key Features

Car Speaker Type: Component
Elements: 1-Way
Car Speaker Function: Subwoofer
Size: 12"
Nominal Power Handling: 350 Watt RMS
Powered: Non-Powered
Technical Features

Peak Power Handling: 1400 Watt
Frequency Response: 18 Hz - 200 Hz
Sensitivity: 96 dB
Impedance: 4 ohm (Dual Coil)
Components

Woofer Material: Metal
Surround Material: Butyl Rubber
Mounting

Enclosure: Non-Enclosed
Top Mounting Depth: 6.50 In.
Mounting Diameter / Length: 10.93 In.
Miscellaneous

MPN: kappaperf121
Product ID: 35266

 

Kappa Perfect 12.1 = single 4ohm coil

Kappa Perfect 12.1D = dual 4ohm coil

He says he's got a 12.1

 

Thank you, got it now. Be careful where you get your specs?
In that case, the sony amp he started with would work just fine, bridged to 4 ohm 500rms.
So, the short answer was yes.

The long answer is: Most mono amps don't give as much power at 4 ohms.
for instance, the prs-d3000spl would give you 500 rms @ 4 ohm, then if you plan on upgrading to 2 subs, you already have an amp that will do 1000 rms @ 2 ohm.