Google recently added audiobooks to Google Play, so you can listen to your books while near your Google Home. To get you started, the company is sending out emails offering a free audiobook for a short time. The deal doesn’t last long, so you might want to check for yours sooner rather than later.
The email doesn’t seem to be going out to all Google Home users (I own two and haven’t received the email), or it may be rolling out to users in stages. According to Droid-Life, the deal is only available for around a week, so you’ll have to act pretty quickly once you get the message.
The discount applies to “eligible titles” so, unfortunately, you might not be able to get exactly the audiobook you want. Still, free is free. If you find one you want, add it to your cart and the price will drop to free during the checkout process.