Subsidized Stafford Loan?

I am eligible for a SUBSIDIZED Stafford Loan but am confused about certain things. Does being eligible for this type of loan mean that I need only repay what they give me (e.g. they give me $3500, I give them back exactly $3500) or will I need to pay them more? What is this about the 1.5% federal origination fee, and the 6.8% fixed interest rate?