I charge $25 a day for 5+ hours. I include basic preschool- have lots of learning tools available, tons books, we sing, talk about life as we learn counting, letters, bake cookies, etc. The moms know I have other things going on (school for my kid, care for a 10 m/o, etc), so they know some days we get a lot done, other days they "just play".
Save receipts for everything!!