This also applies to a car.  Where is lesson #2, #3, #4, etc?

    Carlos, you are asking for a simple answer to a complicated question.  Airplane expenses are divided roughly into two different expenses, fixed and variable, which comprise the total cost of flying. Each item in the expense category varies depending on where you are living, how experienced you are, what type of airplane or other aircraft (helicopter, balloon, gyroplane, blimp, etc.) you own, etc.   Fixed expenses are those which will be the same each month whether you fly the airplane or not. Variable expenses vary with the number of hours you fly each month. The total or these expenses added together and divided by 12 will give you a reasonable estimate of monthly expenses,  Add ten to fifteen percent for unscheduled maintenance and you will be in the ballpark.

A good book which discusses all aspects of aircraft ownership is " The Aircraft Owner's Handbook" by Timothy R.V. Foster.  Your local library or one of the companies on Amazon will have a copy.  It is a good read.   My only comment on aircraft ownership (and I have owned several over the last thirty years) is that like a motorhome, the normal wage owner does not need to own an airplane by himself. Flying and sharing expenses with friends makes a lot more sense unless you can earn enough using the airplane to pay for it.