What's crazy is that my book income is more than my SF condo-rental income. Yet I didn't have to come up with $1.2 million of capital (the minimum cost to buy my condo today) to create my book. All I needed to create my book was energy, effort, and creativity. I truly believe that developing your own online product is one of the best ways to make money.
Residual income is the amount of net income generated in excess of the minimum rate of return. Residual income concepts have been used in a number of contexts, including as a measurement of internal corporate performance whereby a company's management team evaluates the return generated relative to the company's minimum required return. Alternatively, in personal finance, residual income is the level of income that an individual has after the deduction of all personal debts and expenses have been paid.