Attending a private Catholic high school can be quite expensive, with costs averaging about $9,790 per year as of 2012. The question many parents ask is "Is it worth it?" Public schools can provide a good education and don't cost anything beyond what people are already paying as part of their taxes. This could be why only about 10 percent of parents send their children to private schools. Of these students, about 71 percent of private high school students attend Catholic high schools.