Hi. I have heard somewhere that Inmobi allows users to display ads for free until a user's account reach a certain amount of money. I don't know is this true or not. I am actually looking for such a site on which I can advertise for free for at least sometime. Like some companies give some trail or demo things to users. If someone knows about such free sites please share with me and if any one knows that Inmobi does such things please tell me how can I do that.