You obviously need funding to make a business idea work especially if its something that requires a lot of funds. However, funding is not everything. Tech startup Busuu.com recently raised eur3.5m in funds but prior to that they had been operating a lean approach. The company started out as a class project at IE Business School. One of the co-founders said in an interview that this method was because its better to focus on establishing your model as sustainable before focusing on expanding.