If you’ve written multiple novels, and especially if they’re a series, you may want to consider sticking your book in a Little Free Library.

A Little Free Library is a small container, usually kept at the edge of a homeowner’s lawn next to the sidewalk, where free books are placed for local community members to read. Neighbors can place there a book they’ve read but no longer want to keep and then take one they want to read. They are variously known as book trading posts, community book exchanges, Noox (Neighbourhood bOOk eXchange), and pop-up libraries and can be found in all 50 states.

Though you’re giving away a book, hopefully some reader will enjoy it enough to purchase copies of your other books. Or perhaps several neighbors will read the book, discuss it, and each buy other novels you’ve written. Maybe they’ll even buy a copy of your giveaway to keep on their own shelf.
Because of this, always make sure the book you give away has a list of all of your titles as well as URLs to where they can be purchased.