What are some good iPhone photo editing apps for free?

I need some good photo editing apps for an iPhone. I have "fotolr" & "Picart" but i need new ones. Free ones though.

Squaready!

Uh… I had the photo shop one. It worked very well, I only needed to crop pictures flip them and change skin tones very slightly. It worked pretty well for me. I think it's call "ps express"