Denver Preschool Program is expanding free preschool to 3-year-olds Tuition credits for qualifying families The Denver Preschool Program is expanding to serve 3-year-old students. and last updated 2021-05-07 10:32:29-04 A free preschool program in Denver is expanding to offer thousands more slots starting in September 2021. For the first time ever, the Denver Preschool Program (DPP) is expanding to serve 3-year-old children. Since it was approved by taxpayers in 2006, DPP has provided free or preschool for 4-year-olds on a sliding fee scale. âUnlike our traditional program, the preschool for 3s is going to prioritize families in financial need,â said Elsa Holguin, president and CEO of the Denver Preschool Program.