I have not been into car audio for about a year and a half - I lost me truck a while ago.
I used to do some competing and had nearly 10k invested in the stereo alone. For good sound you will have to spend close to 1k in my opinion to get anything decent. Make sure you do some pre-maintenance before you put a sub in any car. The vibrations will destroy anything. Dyno-mat the trunk with a minimum of one layer will stop that annoying rattling sound and help save inner parts from falling apart. I would get some loc-tight - thread locker and use it on as much as you can. Once a few bolts come loose you will never stop the rattling. I have always been a fan of loud nice sounding cars. I can not stand it when kids put a sub in a car un-tuned and pound the shit out of it. Just sound like shit.
I had 3 layers of dynomat throughout the entire truck - actually stripped it too bare metal pulling every interior piece out including the dash. Prep makes a huge difference.
As for a head unit I would suggest spending a little more and investing in something that will work for you. A cheap head unit does not allow you to program the eq to best suit your setup. Not sure if you are going to power just the sub with an amp or just the head unitr. If you are powering every speaker with an amp then spending a few 100 on a head unit is well worth it.
I always liked pioneer never had an issue with them -
http://www.bestbuy.com/site/Pioneer+-+50W+x+4+MOSFET+Apple%26%23174%3B+iPod%26%23174%3B-Ready+In-Dash+CD+Deck+with+MP3+Playback/2822336.p?id=1218354573849&skuId=2822336
http://www.bestbuy.com/site/Pioneer+-+50W+x+4+MOSFET+Apple%26%23174%3B+iPod%26%23174%3B-Ready+In-Dash+CD+Deck+with+MP3+Playback/1750059.p?id=1218289378860&skuId=1750059
You get what you pay for
Both are a bit more pricey but would be a better option in my opinion.
edit: if you don't want to do alot of prep work at the minimum please please put cork or rubber weather stripping around your license plate to stop the rattling