Rutgers Libraries do not have any Harry Potter books available electronically. In addition to your local public library, the Internet Archive has both audio books (American version read by Jim Dale, British by Stephen Fry) and ebooks to borrow for 14 days with a free account.
Caution: although many web sites offer free downloads of Harry Potter (e.g., legitimately, with Audible trial), please be careful with these sources. Everyone loves Harry Potter, including the hackers!