the money a person has available after taxes is

The money a person has available after taxes is usually referred to as 'disposable income'. This is the amount of income left over after all personal income taxes (like federal tax, state tax, local tax, social security tax, Medicare tax, etc.) have been deducted. The concept of disposable income is important because it represents the amount of money individuals have to spend on necessities, such as housing, food, and transportation, and on discretionary purchases, like entertainment, vacations, and luxury items.

Extra: Understanding disposable income is crucial because it directly impacts a person's standard of living. It's the portion of income that you can actually use to support your day-to-day life. The more disposable income you have, the greater your ability to save, invest, and make purchases that can improve your quality of life.