Need a fun Halloween book to entertain your little goblins? Take a look at this free ebook on Amazon. Right now, grab the digital version of Boo and the Backyard Zoo and pay zero dollars! That’s right–this book is absolutely free. But prices on Amazon can change quickly, so make sure the book if still free before purchasing. Remember, you don’t need a Kindle in order to read this book. Use a smartphone, a tablet or a computer.