TheMastersGifts.com, SonLight.com and Amazon.com all carry the answer keys for the Wordly Wise 3000 textbook. The Wordly Wise 3000 textbook has several different books that cater to children in grades K to 12, each with a specific answer key.
Answer keys at The Master's Gifts cost $5 each, as of March 2015. This website carries the answer key for almost every book in the Wordly Wise series. The answer key is the same price on Amazon, but is also available used for a lower cost. On Sonlight, users can purchase a book and the corresponding answer key as a package for $18.