My DD spent one summer in Seattle living in UW dorms. The other summer she rented through an org called Landing which has fully furnished short term rentals in cities. Not cheap though.

I would ask the employer if they have suggestions too. They make know what other interns have done.

Not every offer makes sense and you can only take what you can afford.

Look on facebook or through an alumni network for a summer sublet.

My DC's college is in a big city and has a Facebook page dedicated to people looking for roommates and sublets. People who go to college in other cities post there all the time looking for summer sublets.

Also second the recommendation about looking into college dorms. Some of them are full of camps in the summer, but some are available to interns.

Does her college have an active alum network? Years ago when I was in my first group house (me, 2 college friends and a 4th roommate), a jr at our college posted that they needed summer housing. I’d just found a new apartment with the lease starting in late May, and our group house lease ran to Sept, so it worked out beautifully to sublet my room to the person from my college.

Some internships provide housing (like SERC—part of the Smithsonian). Some schools have grants to help students underwrite internships that do not pay (enough or anything).

Poor kids generally do not take unpaid internships (even though it might help their trajectory).

Looking for summer housing at universities is a good suggestion.