<p>The TI-83 is probably the best thing you can use for the purpose of the course. It does everything for you that the AP test (and probably your class) would require of you. Getting anything more advanced than the 83 is not really a good idea for now. More advanced calculators can do all kinds of neat fancy things (I don't know exactly what because I don't have them), but they do so much that they can basically take the AP test for you, so they are not allowed for use on the test. Your 83 is perfect for now, and if you ever take more advanced calculus you can look into a better calculator later.</p>