I purchased the Texas Instruments Scientific Calculator-30XIIS for my daughter upon entering middle school. She has always had difficulty with math and this caluclator helps her immensely with her classwork and homework.
The 30XIIS is simply the best calculator you can buy beating out any other calculator at any other price. It can do everything for you besides graphing. It has large memory and can handle EXTREMELY large calculations. It's buttons are responsive and do not wear down. It is solar powered so you never need to worry about batteries. And unlike many other calculators, it follows the order of operations. If you need a calculator for school (other than a graphing calculator) you should purchase this one. It will last you several years.