Oh god. When will society see that because another person says, 'HEY IT'S FREE AND EASY TO USE!' doesn't mean it is better, or easier to use than another program.
Photoshop, with a one hour online course, will become the easiest program to use for you.
If you still can't afford/use/work/learn Photoshop, then GIMP is for you. But if you have Photoshop, learn to use it, it will help you in the long run whether or not you are serious about graphics design or art.