You can use GIMP for free (its like Photoshop, and some prefer it) Download here;
http://www.gimp.org/downloads/) :p
Just check the file types displayed, I don't use it, but if your struggling with GIMP, you'd struggle with Photoshop; spend time in the program, takes a while to learn things; I'm a pro in Photoshop, and still don't know half the things you can do in it.