ok everyone: here. This is a free, awesome graphing calculator program that will run on the computer you already own. You don't wanna buy a TI calculator? You don't have to.
EDIT: If you're a teacher, do your students a favor and teach them R instead of TI-BASIC
Actually I talked to my teacher and he was ok with me using it. I just explained that my family didn't have the money to drop on a calculator, especially when there was a free alternative.
Also my school didn't have WiFi back then so I couldn't access anything on the internet. Plus he walked around while students took their test so I couldn't have cheated for long before he would have noticed.
I found the link to the one I used: http://www.graphcalc.com/
One thing I find to be fun is to get some math software and start playing around with it. You can use stuff like GarphCalc (http://www.graphcalc.com/ ) or GeoGebra ( http://www.geogebra.org/cms/en/ -- requires Java) and get it to try and draw mathematical pictures. Start simple and work up to cooler things.
I find that when I want to do something, and I can visualize the goal, researching what I can do to achieve that goal, through reading tutorials and looking at examples created by other people, is a fun way to learn things.