四五快读 is an excellent, low-cost curriculum that teaches 825 simplified Chinese characters through stories and various reading exercises. Our reading skills improved considerably thanks to this series!
The Greenfield 我自己会读 I Can Read series has 96 short, humorous children's stories that are illustrated beautifully and build reading confidence. The CDs give exposure to native Mandarin or Cantonese. In addition, workbooks and flashcards are included.
Spoiler alert: Sagebooks is the very best curriculum for teaching your child how to read Chinese.