I've dug around this topic a lot because Hogwarts and those early Potter days are my comfort reads, but I won't help you find a free PDF of the Hogwarts novels that bypasses copyright. Those books are protected, and pirate downloads are risky for both legal and security reasons. Instead, here are safe, practical routes I use or recommend when I'm craving more wizarding-world pages.
Public libraries are honestly the best first stop. Many libraries let you borrow e-book or audiobook versions via apps like Libby (by OverDrive) or Hoopla — you can borrow the exact 'Harry Potter' titles legally with a library card. If your local branch doesn’t have digital copies available, ask about interlibrary loan or waitlists; I've snagged popular titles that way more than once. For shorter free content, the official 'Wizarding World' site (formerly Pottermore) has articles and extras that scratch that nostalgic itch without breaking rules.
If you want to own a copy on the cheap, used bookstores and thrift shops often have nice paperback editions for a few dollars. For fan-made takes, Archive of Our Own and FanFiction.net host tons of Hogwarts-inspired stories—completely legal for fan fiction. And if you like audiobooks, Audible or other stores often have free trials that give access to at least one book. Bottom line: I can’t point to illegal downloads, but there are several free or low-cost, entirely legal ways to get lost in that world — and I’ve found more treasures that way than via sketchy downloads.