How can I promote my website on the Internet?

Which are the most economic ways to promote website on internet or off the internet?

• I am starting up a website based on seller meets buyer and vice verse, both the parties find the best hand, eventually they make a deal too and live happily ever after. All I will do in this consilience is to provide them a platform and smiling around with every fruitful transaction made between them from my platform. Personally I feel its not a bad idea as already some of the players are there in the market, and they are doing well too. So somebody please help me in this to make sure I reach people as many as I can. The reason I am saying economic is I don't have much to spend on marketing. Industry has seen so many rising stars without blindly spending money for marketing. Flipkart is one of them.

• Answer:

  The local Dutch market dominator, http://Marktplaats.nl, did it by offering ad for free int he beginning, then moved on to charging 6 euros for ad for items costing 200 euros or more, and either 9 or 12 euros for certain types of ads (commercial real estate, real estate, cars, business services, vacation, water sport, that kind of stuff).  so 30% of the ads are paid and 70% are free; they are making money.  They also instituted an automatic extension of ads in those sections, which probably increased to the profits even more.