I have my daughter in private school and it costs in the area of 6000-6500 a year after all fees are accounted for. We love it for the fact that there are smaller class sizes (her kindergarten class is about 18 kids and there are 2 teachers in each kindergarten class). Also, one of the main reasons that private school was important to me was that I went to St. Monica's in Converse when I was a child (until 4th grade) and by the time I moved to public school, I was nearly a year and a half ahead of where they were at. True to form, my daughter is learning things that seem to be ahead of the curve for her age group (in fact the lady at her day care tells me that she gets kids to work on their homework and my daughter's is most challenging). My wife mentioned to me that she loves the fact that when we drop off our daughter in the car line, that the teachers working the car line always take the time to say hi to my daughter and pay attention to the kids because when she was taking my step daughter to car line when she was little at a public school, the teachers would either be talking to each other or just otherwise not paying attention to the kids. CTOA also brings up a good point in that the parents are paying for this so you can bet that they are involved. Worst case scenario, a household must volunteer at least 10 hours a year at the school.
I don't know if all schools have it, but if you were worried about the expense, there is a program (at least at our school) where you can be one of the guys selling beer/wine at the stands at spurs games and other att center events and you get a percentage of the sales of your stand taken off of your monthly tuition. Also, the tuition at our school is spread over 12 (instead of 10 months). Let me know if you have any other questions.