There is this saying in Chinese, 助人为快乐之本, which roughly means the basis of happiness is generated by helping others. A research shows that money might buy happiness—when you spend on others, which makes the above more correct scientifically.
However, the first two results from surveying how do people spend their money might have the cause and effect in the other way. ... Why do I suggest so? The people who gave more to charity are probably already happy people who have or feel that their own needs are satisfied, and therefore see a part of the money they have as extra and are willing to give to charity. Of course, I don't deny that the acts probably makes them feel happier and they'll continue to do so.
The third result from an experiment, where some people were given money and also told how to spend them, specifically shows that it is the way they spend money that influence their level of happiness.