As a junior, even if are dependent for financial aid purposes and your parents are Bill and Melinda Gates, you can still qualify for what's called a Stafford Unsubsidized Loan for up to $5,500. There is no credit check and no co-signer--you the student are the borrower for this loan.
Interest accrues while you're in school at a favorable rate. Currently, they're variable rate (maximum 8.25%) but loans disbursed after June will be a 6.8% fixed rate. And even if you aren't eligible for grants, you may still be able to get a subsidized loan. As the previous poster said, definitely fill out the Free Application for Federal Student Aid (at
http://www.fafsa.ed.gov). There's lots of good information at
http://www.finaid.org and at your school's Financial Aid Office.