My website is about two weeks old now and i am looking to build back links for the site. I know that manual submission is the best way to go but I want to know if it is worth the effort and money to have my site auto submitted to directories or buying links in bulk. I was thinking of trying to find 100 pr3 and up link if possible. Also if you have any suggestions on where I should purchase these links let me know. Thanks!
Personally, I think that buying links is a the worst possible method. Make sure you read Google's TOS about purchasing links that pass "juice." I truly think starting slow, submitting to some directories, blog commenting, forum posting, social media/bookmarking, and most importantly, creating quality content and services that others will naturally link to is your best bet. Especially since your site is new and a huge increase in purchased links could look unnatural to search engines. So my suggestion on where you should purchase those links would be...nowhere. Do it naturally, create a valuable resource for others, and manually build a few links yourself each day. If you need any help with link building, please feel free to contact me.
Manual is really the only way to ensure you have gotten your link submitted to the appropriate category when it comes to directories. There is only a finite amount of them (granted thousands) but once you submit to them all, its just a daily upkeep for the newer ones. You can pay for other services such as forum posting where you indirectly get a link along with brand awareness so I see nothing wrong with that.
From my knowledge hitting a new site with bulk and usually low quality links will not do you any favors, you might get a quick boost but then you will drop back. Regular steady link building is best.
Building links too quickly for a new site is not such a good idea. It should be done naturally and over time. If its done too soon your site can be penalized by Google and could get sandboxed.
You can do start with blog comment, forum posting and manual link exchange and please don't purchase links in bulk.
Rather than buying links, you should probably get 'free moderate links' like directory submissions, article submissions, blog comments etc.