Everyone starts somewhere. I learned on a pirated version my friend gave me by just using it. Trial and error is the best way to learn.
If I had the money though.
But don't get yourself down thinking that you suck. Just do what you can, use your imagination, practice, fiddle, and eventually you should be able to do something you can like.
This is what I did anyway!
The PhotoShop contests on Fark.com are a great way to just masturbate your mind and improve skills/get ideas.
Plus it's fun, because it gives a reason to do a piece.