From my experience the Kicker Comp VR line is an amazing sub. I have had two 12" CompVRs running 100watts over RMS for close to 4 years now. Alpine amps are very high quality as well and have lasted me a loooong time.
"Bass Packages" are ok... but normally you get no where near the power the subs are able to push. The Amps in these packages are normally way below the subs to keep cost down. That plus the wire they use is normally sub par.
Check out places like Ebay, Amazon, Sonic Electronix (great prices, horrible shipping cost), ect. and look around, read up on some stuff, and get a feel for where you want to go.
I found this for you, amazing price if you ask me:
Amazon.com: Kicker CompVR 07DCVR122 2-Ohm 2 Subwoofers In-Vent Box: Electronics
Thats 2 12" DVC 2-ohm subs in a perfectly matched Vented (and good looking) box for $260 shipped
You could get just the subs:
Amazon.com: Kicker CompVR 07CVR122 12-Inch 2-Ohm DVC Subwoofer: Electronics
Total around $175 for two shipped.
Alpine amp that does 1000watts x1 @ 2ohms (great match):
Amazon.com: Alpine MRP-M1000 - Amplifier - 1-channel: Electronics
$270 total.
May reach the $500 price range you mentioned... but trust me... That Kicker/Alpine combo will give you plenty of bass for anything.
You could cut down on the cost as well and just go with one sub and a cheaper half power amp if you just want "some" bass and not trunk ratteling bass.