For a true "budget" setup, I think this is a pretty good deal:
http://www.walmart.com/catalog/produ...uct_id=7788881
You'd just have to adapt for the speaker sizes that come with it. If you're not "great" with installs, you may want to tackle replacing your stocker 4 inchers in the dash and just skipping the rears and putting a small box or two behind the rear seat for a set of 6x9s or something. The rears were kind of a pain to replace, having to pull the plastics and then cut to adapt for a bigger speaker (wasn't settling for a 5.25 after all that work).
Just a thought(s)...