Cost of creating a social networking site?

How much would it cost to create a social networking site? (I mean if you paid someone to do it)

Cost of creating a social networking site?
Not much... but there are so many free choices why not do it yourself? See GraffitiCMS, blognet and others.
Reply:how would you make profit though?
Reply:it will cost a bit of money. But you will also need your own servers which will cost a lot.