100% of your needs is based on just that. If your parents have lots of bucks, then your "needs" are less. If you have a job, then even less. So each school will use the FAFSA forms, look at what you and your parents have in terms of investments, cash, savings, jobs, income, home.....and then offer you aid based on that. The aid can then be made up of "free money", work study, loans from the school or helping you get loans from somewhere else like a bank or government.
And yes, it does vary a bit by college, however all will use the FAFSA and or Profile forms to determine your parents and your "net worth".
Remember, that if you and your parents make less than 50K per year and have little or no investments...etc, many schools will offer you "free money" or reductions in tuition. This is why you should always pick schools based on anything else but how much they cost until you know exactly how much and then you can pick the school based on the best deal for the money.