Photoshop Elements – Does it stand alone? Genereal Photoeding ?’s?

A question I have is can I use Photoshop elements 7 as a stand alone program or do I have to actually have Photoshop CS or something like that. Is Elements an add on type of thing or can I use it by it’s self? Another thing-I I hear gimp is a good program but I was wondering does the free version have a brushes option( I know I’d have to dowload them if so.)