I am too poor to afford Photoshop, but I have had good results with the clone stamp and healing brush for imperfections. I found an ok clone stamp with the new paint net, but there is no healing brush. I guess it's a new thing that needs time to come out in the free version. If you use the clone stamp first, then use the healing brush you can blend away your corrections, for a natural look. Does any one know about a free program with a healing brush? I don't even use layers. I don't need all of Photoshop. Below is a link to my new Flickr account. If you add me as a contact, I will be sure to add you back. Thanks.
Here is a link that might be useful: My Flickr Page