I'd like to offer free advertising?

[Saiful A]

hi.. im developing a kind of start up social network with blog-like thing.. but, there's kind of lot of empty space around my site.. so, i was thinking of putting some ads.. not too much.. just enough to fill some holes.. i'm not planning on generating any revenue.. not yet.. so, i'd like to offer free ad space.. is there any such service? i couldnt find any.. any service that would accept low traffic website for their ad service should be acceptable too..