I know directory submission is hard when we try free submission.
Because maximum High pr site want to money. But if you want to free you must need to wait. But other type of backlink you can create free just need to collect high pr link and need to submit. like social bookmark, Forum post, blog comment etc.
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Backlink is basically a link which is directed towards your site from other site. Backlinks are very important and can be made by using link building techniques. By using these techniques any one can build backlinks Social Bookmarking, Article Marketing, Blog Posting, Blog Commenting etc.