Now factor in scholarships and grants. Each school will offer you a different package of financial aid. If you get loans, the interest rate will make a difference on how much you have to pay back.
Most school's websites will have information on average costs, scholarships, grants, etc. and give you an idea of what your debt will be at the end of the four years. I'd suggest you go to a few schools you are interested in and see what they say.
It all depends on your financial aid package that you receive. It also depends on the school that you attend. Check out the statistics of each school you apply for as far as expenditure on tuition, housing, books, food, etc. Each school is different. Also you might want to take out a loan dependent on what you are offered for your financial aid to each school you applied to.
There might also be a TAG program at the schools you apply to. TAG is where you take classes at a community college and you will be guaranteed a place at the school that you originally applied to at the end of the community college classes. The program might be called something different at some of the schools. I know that UC Davis has this program.
Also apply for scholarships. This would help at a great deal.
State Univ are highly subsidized and they will cost you the least. Each state varies in the tuition and other expenses.
Check out the state univ website to know how much it cost. It is detailed and most state univ can give you credits for the AP courses you have taken in the high school and if your 4-year cumulative GPA is above 3.5 - state will also give you partial or full scholarship.
Your essay and the subject you write about weighs a lot.
You can also consider 2-yr at a community college and transfer to the state univ provided the state univ accepts those credits. You will need to do homework here to find out what is transferable.