Quality preschool programs can be defined but it takes some thinking. First of all, you need someone capable of developing strong preschool lesson plans, and implementing them. But that's only the tip of the iceberg.
If you have a good teacher who is creative and intelligent, but have large class sizes, that teacher won't be able to perform the job she was hired to do. But staff is the most important indicator of a quality preschool program. If a program offers computers, and a "Spanish program" but hire non-educated people at $6.00 an hour, what does this indicate about this program? This says although they want to appear to offer a "Quality preschool curriculum", what they are offering is glorified babysitting. Why pay $200 a week for babysitting when your child can be learning and thriving in a great preschool environment.
So when you are looking for a place for your child to go to preschool, think about what they are offering you, and ask about the qualifications of those you trust with your child's preschool education. If you opt for the low cost option automatically you may short change your child's education.