Write few articles and submit these to article submission directories, you will get both the backlinks and traffic as well.
If you are referring to social bookmarking site backlinks, you can try 1. https://onlywire.com/signup_sel?plan=pro ( 1000 submissions $10/month, 40+ sites supported, once set up everything will be auto ) 2. http://www.socialmarker.com/ 3. http://socialposter.com. Hope this help.
If you mean by backlink help for free, then you should look out for some article submission directories, RSS submission directories, social bookmarking sites and forums. Because this is how you are going to get free backlinks and yes go for some link exchanges too with the blogs in your niche. If you mean backlink help by buying the links, then you should check out the Link Sales section on DP and buy, sell, trade sections in other forums, you might get some good deals with quality sites.