Nobody really knows how to calculate the "total cost of ownership" of a general piece of software.  So a good lawyer + accountant can prove whatever point they are paid to make, and they regularly do.

Let me try a simple estimate of how much the average total cost of the ownership of MS Windows is. Let's add the fortunes accumulated by all the MS Windows software makers. Add all the salaries of all generic Windows programmers, consultants, support and training personnel, IT management,  etc. Now, add the losses customers must surely have suffered while the software corporations were presenting them with "features" so as to achieve their current monopolistic status. Divide this figure by the number of years (whatever timeframe you selected), and the number of MS Windows users (only in the countries in which software is normally paid for).  Here is the TCO of MS Windows. However you count it, it will be many thousands of good US dollars per average joe per year. You didn't pay that much money? Well, you must have, it has just been hidden from you. Yes, developed countries waste billions every year on software.

How much did Linux cost? Hardly anything. The number of users is much lower, too, but you will be hard pressed to come up with $10 per user per year.

Yet, in my opinion, the total cost is not what matters the most. What value did I receive for my money?  You would have to calculate the total value of ownership (TVO?), then subtract from it the total cost of ownership (TCO) to obtain the "net benefit of the ownership."

I guess accountants only talk about the TCO for software "necessary for doing business," and thus skip the issue of value and benefit. There is no value in the normal commercial software, it is just the necessity for doing business these days.  Well, Linux satisfies my computing necessities at zero monetary cost, and the personal pleasure and learning value is just great.