The concept here could be, if someone pays for your lunch then there is an implied obligation to pay them back, clearly this is based upon the paradigm of value being some transferable commodity that can be encapsulated in notes or coinage of some sort or more accurately in today's world, digitised bank records and can be passed from one person to another. But, couldn't I buy you lunch and not expect you to pay me money back in return?
The concept could be broader and the obligation could be to give some value back in another form (you scratch my back, I'll buy you lunch) -- this mixed-metaphor still describes "no free lunch". But I would still maintain that I could buy you lunch and not expect my back scratched. I guess I should've put that in quotes!
It could be argued that nothing is free and that ultimately someone is paying for it, whoever pays me sufficient money such that I can make my magnanimous gesture of a free lunch, ultimately paid for your lunch. I don't hold with this -- there are some natural resources that are in such abundance and are not (or should not) be under the control of an assumed authority to meter out. Resources that could be considered to be free for all. However this then brings us to The Tragedy of the commons, which argues that free access and unrestricted demand results in depleted resources through over exploitation, probably permanently.
The suggestion is that each individual realises that grabbing what they can for themselves, even when they know it will damage the whole supply, is in their personal best interest and so they cannot help themselves. In the modern solutions section of the graffiti-pedia page it starts its description as "in the absence of enlightened self interest....". This is the tragedy! Our default start position is, "absence of enlightened self interest". We assume that as individuals, governments, corporations and society we cannot take only what we need, we have to grab it all quick before it goes - bugger the rest of you. We cannot see that if we take what we need, dare I say it - take nothing if we don't really need to and leave it for someone else, that this is actually in our own best interest.
No one owns the internet. Ok, people charge us to get to it but eventually - as is starting to happen with telephone lines, that capital expenditure is written off and there is no need for the owner to generate income simply from using it. There is a continuous hum about free internet sites starting to charge, that commercialisation of the internet is expected, we naturally assume it has to make money. I don't. I hope the components that are free, remain free and that many other aspects become free. That corporations, governments and society realise that there is a phenomenal possibility for enlightened self interest in the whole world creating and maintaining free and open global dialogue.