Replying to Help me out

im a jr in highschool, and im gunna take graphic design courses next semester (i wanna go into graphic design in advertisement) i wanted to basically practice for it and i was looking around for programs to use on my computer to practice and try some stuff. Adobe Illustrator CS2 looked good and i want to save up for it. Anyone have it? and would you suggest buying it or do you have any ideas for a free download anywhere where i can just try some stuff. if you can help me out thanks