Dr. Elfrieda Hiebert has a completely free website with literacy materials! Visit Dr. Freddy Hiebert at textproject.org
One of our favourite resources is her collection of 80 non-fiction articles (approx. upper elementary level). They come in 5 (discreet) levels of difficulty. Each is a one-page, non-fiction article with colour photos. You can find the FYI for Kids! Articles and more here.