GIMP is free, and very fully featured, however, I have been working in Photoshop since PS7, and working in GIMP is like a completely different universe for me. If you really want to get into design, I recommend you start with PS. Even if you do buy it, Elements is really worth the $60 or $70 you'll spend on it.
Of course, if you're thinking of spending $2,500 on Adobe's Master Collection, may I recommend you uhh, look elsewhere, and spend that money on a Cintiq, they are pretty awesome.