Most of Tozer’s books are still under copyright, but a few happen to be in the public domain, including the classic The Pursuit of God. Although that’s the only one that’s in multiple formats, I’m leaving these links here in case more of them show up in the future (like Total Commitment to Christ, or How To Be Filled with the Holy Spirit).
Helpful tip: If you’re in a pinch, you can borrow many Tozer books with digital library access from the Internet Archive. All you have to do is sign up, and you can borrow a book for two weeks at a time.
Free A. W. Tozer books (PDF) on the Internet Archive (10+)
Free A. W. Tozer audiobooks on LibriVox
Free A. W. Tozer books on Project Gutenberg