I want a Mac

So I really hate my computer. It is like 4 years old and I want a new one so bad. I was using my friends Mac book for the garage band assignment and I was having so much fun with it. I really want a mac but they are so expensive and I just got a new net book to travel with. Although the net book is great and I am very happy I got it, I need a larger laptop to hold all of my files and to create media. My laptop now is constantly crashing and has so many viruses on it. I can't even download new programs because it keeps saying I only have 75mb left on my hard disk. It is so annoying and frustrating and I just want a computer that works without any problems.