"Free goods are almost a myth in economic terms nowadays."

 In classical terms:

"A good or commodity in economics is any object or service that increases utility, directly or indirectly, not to be confused with good in a moral or ethical sense (see Utilitarianism and consequentialist ethical theory). A good that cannot be used by consumers directly, such as an office building or capital equipment, can also be referred to as a good as an indirect source of utility through resale value or as a source of income. A 'good' in economic usage does not imply moral acceptance or even legality.

 

"If an object or service is sold for a positive price, then it is a good since the purchaser considers the utility of the object or service more valuable than the money. Some things are useful but not scarce such as air and are referred to as free goods." http://en.wikipedia.org/wiki/Good_(accounting)

 

A legitimate question exists as to whether there really are any truly free goods, since the classic free goods are things of nature such as air, water and sunlight. However, for these things to have full and complete utility, they need to be relatively free from chemical and/or biological contamination. In a less technologically developed time, perhaps it was easier to find unpolluted air and water and sunlight unhindered by smog. Those days are long gone. If we encounter those things in the modern world it is because pollution has been stopped either through regulation or through not allowing polluters to externalize their costs by dumping pollutants into the air and water.

For example, in the age of Queen Victoria rickets was a common problem in children in the industrialized cities of the British Isles.  http://en.wikipedia.org/wiki/Rickets  This was the case because of the latitude of the islands, coupled with the air pollution that significantly reduced air quality,  diminished the amount of sunlight that actually reached children in the cities. So even back as far as the 19th century, in many places, pollution had drastically eliminated the possibility of there being free goods.

Leaving that bit of intellectualizing aside for the nonce, I long have subscribed to the theory that something's value is determined by its utility at the time that it is needed. So, while normally in a developed, civilized area water is relatively available, if you find yourself in a position where potable water is not readily available and you become thirsty, potable water becomes much more valuable whether you wind up paying for it or not.

A few years ago, my wife and I took a week's trip to Bermuda. The second day there, we took a short hike--maybe two miles to go to a beach away from our hotel. Not having realized the scarcity of potable water on the island, we neglected to carry any water with us. When we reached the beach, we would have gladly paid a steep price for a drink of water, since the weather had become unseasonably warm. Fortunately for our financial health, we saw a small, rusted but usable water fountain that worked. The water than we drank then was of significant value to both of us right then. It had a lot of value even though we hadn't paid anything for it. 

I'm sure that some people confuse price with value. I haven't been one them in years and years. What cured me of that error was something that happened in Economics 101.

Our professor asked the class if they could tell the difference between a popular cheap brand of vodka and a more expensive brand. Several students in the class were dead set that there was a major difference. They were quite embarrassed when he told the story about a consulting engagement that he had worked on in graduate school for a major distiller. The vodka connoisseurs in our class had trouble believing that the cheap and the expensive vodka was all manufactured and distilled the same way and that all the vodka produced came out of the same spigot at the bottling plant, the only difference between the two price levels of vodka was the labels put on the bottles. I think that did a lot to make me understand the difference between price and value.

If someone pays more for an economic good than what it is worth to him, the person is economically foolish.