If your pictures aren't perfect, you need a powerful image and photo editor. With Photoshop out of your budget, you'll want to give RealWorld Paint.COM a try. This free program gives you such a wide assortment of tools for editing and drawing that will satisfy anyone except those who need high-end power.
It gives you a whole assortment of tools, including for adding effects, creating graphics from scratch, changing the color attributes, and far more. It even lets you use pre-existing Photoshop filters by dragging them into the program. The program also uses layers as well as an assortment of tools photo editors will welcome, such as Gaussian blur. It has a number of the higher-end features of the Open Source image editor The GIMP, although not quite as many.
With all that being said, you should also realize that this isn't the program for people who want to do simple photo editing, such as cleaning up red eye, or automatically fixing problems with a photo such as bad color. It's designed as a higher-end tool, and for basic photo editing, you should look elsewhere. But those looking for a tool for more powerful work without spending any money will welcome it.