Assuming this is correct he had money from someplace.

https://www.investopedia.com.cach3.com/university/elon-musk-...

"After two years at Queen's University, Musk transferred to the University of Pennsylvania. He took on two majors, but his time there wasn’t all work and no play. With a fellow student, he bought a 10-bedroom fraternity house, which they used as an ad hoc nightclub."