In 2017, the government financed roughly $100 billion in student loans and provided about $30 billion in grants and $30 billion in tax preferences. A report from the Congressional Budget Office (CBO) examines the impact of such aid and a number of approaches to changing it.
The report can be obtained at https://www.cbo.gov/system/files/115th-congress-2017-2018/reports/53736-postsecondarystudentaid.pdf.