Many self - published authors have their own websites where they offer their werewolf romance novels for free as a way to gain readership. You can search for werewolf romance novelists through search engines and then visit their individual websites to see if they have free offerings.
Goodreads is also a great place to start. While not all the books there are free, it has a large community. You can search for werewolf romance novels and then check if they are available for free on other platforms. Some authors also post links to free versions of their books on their Goodreads author pages.