I have been using NCSS in my high school class room for 22 years. I find it very easy to use and my students use it to calculate their results for their lab reports, science fair projects, and now they are using it for AP Research projects. It can be used for everything from the basics to the most advanced statistics. NCSS is very affordable for any high school budget.
"I have been using NCSS for almost 20 years. I absolutely love it. It does everything [I need that] SPSS or SAS does, is more reasonably priced and user friendly and has wonderful customer support. If you have a problem, when you call a real person (who created the software) gently talks you through it. It is a great product and a great company."