A series of graded readers for early stage reading. The levels progress from 300 to 500 to 750 words.
The stories contain a lot of repetition to ensure learning but at the same time tell more entertaining stories than you'd expect at this level of Chinese proficiency. A far better alternative to reading children's books which are the other option at this level.
The link goes to the official site of the graded reader series. More details about the books are available here. If you are interested in purchasing they can be obtained on Amazon or (for much cheaper - less than 20元 each) at a Chinese bookstore.