One of the many things I am grateful to my alma mater (Smith) for is that they have a program where every student can access a one-time $2,000 stipend to be used while doing an unpaid summer internship (it actually might be more than that now, I used mine way back in 2001). That wouldn’t be enough to let you live in New York or DC for a summer, certainly, but I was able to use it to intern in my state governor’s office while living with my parents, without having to get a full-time summer job on top of interning 3 days a week. It in no way got my CV to the same place as my classmates who could afford to take unpaid internships every summer, but at least I had some non-retail experience to put on there when I was graduating and looking for my first grown-up job.