Quick heads-up: you won't find a legal, free PDF of 'Harry Potter and the Half-Blood Prince' floating around in good conscience. That book is still under copyright, so any full PDF offered for free on random websites is almost certainly an illegal pirated copy.
I get why people hunt for free versions — it's expensive to keep up with everything I want to read — but those shady downloads carry real risks: malware, corrupt files, awful formatting, and of course the ethical problem of stealing an author's work. If cost is the issue, there are a bunch of legit options that feel just as convenient. My go-to is checking the public library's digital lending via apps like Libby/OverDrive; sometimes my library even has the e-book or audiobook ready to borrow. Sales on Kindle or buying a used paperback are also solid. 'Harry Potter and the Half-Blood Prince' is one I usually prefer owning in print, but borrowing it once is perfectly fine too.
Bottom line: avoid the sketchy PDFs and use a library loan or an authorized retailer — you’ll get a clean copy and sleep better at night.