I'd like to make a megathread for some really good free software. I have a couple to recommend.
1st: Paint.NET (http://www.getpaint.net/)
A really powerful, photo editor. Supports plugins that can add functionality like the ability to open up and save .psd files.
2nd: Blender (blender.org)
A really good 3D animation/sculpting program. Takes some getting used to, but really powerful nonetheless. Supports plugins
Add some more down below!
1st: Paint.NET (http://www.getpaint.net/)

A really powerful, photo editor. Supports plugins that can add functionality like the ability to open up and save .psd files.
2nd: Blender (blender.org)

A really good 3D animation/sculpting program. Takes some getting used to, but really powerful nonetheless. Supports plugins
Add some more down below!