i am coming to lausanne next year September from Africa and i need help about housing information and the cost of houses.
maybe meet a friend who could help assist for the first few days.

You should read the STICKY thread on this topic first.

Like most Swiss cities it is very difficult to find a flat in Lausanne and most expat residents have at least a couple of people in their circle of friends/collegues/acquaintances who are also looking for a flat so you may not get people leaping to help you. Sorry!