This is free site with no payment for any kind of posting or knowledge sharing with the world
Instead you will earning, from Google Adsense revenue and good posting will also give you cash credits from the webmaster.
So share your knowledge with for free and earn from different sources
Your question is not complete?
You are talking about which site, if your are talking about My Benguluru its free, you need not to pay anything here. your presence here will give you something, if you are able to answer any question in forum, if your answer is of some value, then you will get the credit for it.
Even you will be credited for posting resouces in resoucres section.
I hope you got the point.
You don't have to pay but contribute and exchange of information is very important as it is an educational website for all.It will benefit you in terms of knowledge and monetary way through utter hardwork and patience.
All the best