Paint.net
Its like a mix between paint and photoshop. I use it only because of layers, I can draw something out and if I dont like it I just delete that layer.

Like the one I'm working on now, adding my initials and CB handle to the gryphon picture and Im using layers to get fonts, sizes and positions right.
If you like playing around with stuff on the computer I'd look into the paint.net, I got it because I lost paint on my old computer and just stumbled onto it...plus its free and havent had any viruses from it.