I couldn't agree more with all of the posters who are advising you to save $$$ on undergrad and then aim for the top law schools by grubbing up a stellar GPA and an excellent LSAT score. This is exactly what I wound up doing, and since I am now just as admitted to Harvard Law as those who attended pricey Ivy League undergrads, I couldn't be happier about this decision. Other than the top rungs of legal academia, which I think might be somewhat difficult for me to attain without an undergrad degree from a "name" school, I believe that my college choice won't have much of an impact on my career prospects in the legal field.
As an added bonus, because attending a more affordable but lower-ranked institution will most likely make you something of a big fish in a small pond, you may be able to develop close relationships with professors who are impressed by your comparatively exceptional academic abilities. This can lead to great recommendation letters!
If you're not entirely sure that you want to practice law, however, this might not work out so well for you. I feel that the best thing you can do for yourself to determine if you will eventually be able to get into a top law school is to take a properly timed LSAT PrepTest and see how you score before selecting a college with the goal of ultimately attending law school in mind. I took my first timed PrepTest during my senior year of HS just to see how I would do, and when I revisited the exam to commence serious prepping during my junior year of college, my initial diagnostic score had increased by all of one measly point.
If you score in the 160s or above on your first timed test, I think you've got a good shot at being able to work your way up to the 170s with further prepping. If you're below 145, in my opinion it will probably be a struggle for you to get your score into the range that top schools (assuming that by "top" we're talking "top 14") look for, and you might want to consider other careers if you're determined to attend a top school or not go at all. Good luck!