Now if I wish to acquire a Saturn, I simply go to the owner of the Saturn and pay money for the car. I do not need to have something of equal value that the Saturn owner wishes to have. The double coincidence of wants is unncecessary. In common usage, the terms money, income, and wealth are often used interchangeably. But to an economist, money and income are very different things.
Income is the flow of revenue over a particular time period.
For an income measurement to make sense, one must define it in terms of a particular time period. Without a time qualification, income could refer to almost anything. Wealth is the value of your stock of assets at a particular point in time. Your assets are things of value that you own. For example, your house, stocks, car, and funds in your savings account are all part of your wealth.