Like Norcal said, at least $200 for a head unit, and about $100 for a good sub. Do you want two subs, or just one? I went with two for looks only, but a single sub with enough power is more than enough unless you want to compete. Going with a single sub will save you some money. As for specific brands, they all have their good and bad, and everyone likes something different. I'd take a look at some of the different car audio forums out there and do some research. The one I used the most was
Sounddomain.