In general, public are more favourite in buying a mansion out of economical considerations. Including the population who bought the residence for their own use or investment. For instance, people may find it is more beneficial for them to buy a dwelling rather than renting one because the month’s mortgage or the rent can be approximately the same. Furthermore, the amount of effort or time of renovation and decoration should also be counted into the cost of owning or renting a living place. Other than that, some people intend to make a profit by investing their money into the housing business, especially in some world-class cities where the house price rockets up rapidly, such as New York, London and Shanghai. Whereas, this may lead to a problem that more and more young people are not able to afford to buy a house in those cities.