One of the six rules is understanding the three basic types of income. Earned income, as the name suggests, is where employees work certain hours for a salary income. Portfolio income is where people invest in stocks or real estate with the aim that they go up in value to then sell them at a higher price. Passive income is money coming in regularly, for example, income from rental properties, from a business or a limited partnership, or royalties from an online course or a book.