If you're outside of Toronto but in Canada, check out my Square store: hardcover
If you're in the States, your best bet is probably directly through the publisher: Guardian Angel Publishing.
Or you can get your copy through Amazon, Barnes & Noble, Google Books, or Indigo/Chapters! Just search for the name, "Sloth the Lazy Dragon"! Also, you can find it in several indie bookstores, including Ella Minnow Children's Bookstore in Toronto, Owl's Hollow in the Stratford area (outside Charlottetown) of PEI, and Kidsbooks in Vancouver can help you out, too!