If we think of nothing as a zero, then it may be free but the place to keep it might have at least some cost. Paper is cheap, and computer storage is probably even cheaper, but it does have a cost.
Actually, zero as we know it today, was not discovered until about 900 AD in India. Before that, not only was nothing not free, it didn't even exist.
Of course we could also look at nothing as the absence of things. That would be the famous vacuum that nature abhors. But now science tells us that nature seems to have created a lot more nothing that anything else. We are told that the vast reaches of intergalactic space contain either nothing, or very little.
But here on earth, vacuum is not free. It takes both equipment and energy to create and maintain a vacuum. So mother nature is a hypocrite. She abhors a vacuum here on earth but she has a huge stash of vacuum in outer space.
When we look at things from a quantum point of view, it may be that nothing doesn't really exist. I guess the uncertainty principle keeps us from knowing whether there is something in empty space. It may be full of virtual particles trying to become real, or it may contain lots of nothing.
The supply of nothing may diminish as we grow older. When you ask a kid what he is doing, he is likely to say nothing. Adults, on the other hand, almost always claim to be doing something.
But the human race has made some progress. Modern people know nothing a lot better than past generations.
The price of nothing is difficult to measure. Nothing is not traded on commodity exchanges. There seems to be no government agency tasked with ascertaining the price of nothing. Actually that is logical. The government does not seem to know the price of anything. Why should nothing be any different.
We could say the opposite of nothing is anything becase some people don't know anything and other people don't know nothing. Put them to gether and they don't know everything.
Anything seems to be almost as hard to pin down as nothing. I know sometimes I don't seem to know where anything is. And, of course, you never know what anything might be doing. It could be anything. But anything is easier to price than nothing. The chances that anything would be free seem to be minimal, unless that anything is lunch, then it can't be free according to a well know law of economics.
Of course there are more reliable members of the thing family than no and any. Something may be reasonable most of the time. Such a thing is usually nice, but also rare. It seems there is usually no such a thing.
But then there is the authoritarian everything. Everything is never content no matter how many things he names. If nothing is free, is everything cheap?
That thing, this thing, and what thing are nice, but they seem to encourage finger pointing.
All things considered, I still don't know the price of nothing.