[DELETED]

Deciding the cost of a project is hard to do with this type of project. There are too many things to consider. Competent programmers are not very good designers, and vise-verse. For example you would need a programmer to write the back-end for your site and designer to make it all look pretty. When you are talking about completely custom work, that can raise the price significantly if you are not careful. Also make sure your programmer has the skills needed for your project, I have seem too many people pay way too much for junk. I good programmer will have a portfolio of systems they have built in the past. Building a custom site is a major undertaking, so do your homework and research.

Depending on what exactly you want to achieve, you could start from a open source social network (like lovdbyless.com, there are more similar ones out there) and hire a programmer (check out odesk.com or elance.com) to add the missing functionalities.