Actually, yes, you should sometimes share your talent for free.

Adam Hess is a ‘comedian’. I don’t know what that means these days, so I’ll give him the benefit of doubt here and assume that he’s someone paid to be funny rather than someone living with their parents and occasionally embarrassing themselves at Saturday Night Open Mic. I came across his tweet from yesterday, in which he attempted some sarcasm aimed at an advertisement in which Sainsbury’s was looking for an artist who would, free of charge, refurbish their canteen in Camden.

Hi @sainsburys I now take food from you without paying because it is a great opportunity for you to impress me pic.twitter.com/GHejafiWVl

— Adam Hess (@adamhess1) May 12, 2016

Now, I’m married to an artist. I have dabbled in art myself, though with the acute awareness that I’ll never make a darn penny anytime soon given my utter lack of a) skills, b) talent. As such, I have a good deal of compassion for artists who are upset when clients, especially fairly wealthy ones, ask young artists and designers at the beginning of their career to create something for free. You wouldn’t tell a junior solicitor or a freshly qualified accountant to do your legal matters or your accounts for free to ‘gain experience’, ‘get some exposure’ and ‘perhaps get some future business’. It invalidates the fact that artists are, like any other profession, working for a living and have got bills to pay.
Then there’s the reverse of the medal. I spend my life in a profession that has a whole culture of giving our knowledge, skills and time away for free. The result is an immense body of code and knowledge that is, I repeat, publicly available for free. Perhaps, if you’re not in the tech industry, you might want to stop and think about this for five minutes. The multi-trillion industry that is the internet and its associated revenue streams, from e-commerce through Netflix to, uh, porn (regrettably, a major source of internet-based revenue), rely for its very operation on software that people have built for no recompense at all, and/or which was open-sourced by large companies. Over half of all web servers globally run Apache or nginx, both having open-source licences.^[1] To put it in other words – over half the servers on the internet use software for which the creators are not paid a single penny.
The most widespread blog engine, WordPress, is open source. Most servers running SaaS products use an open-source OS, usually something *nix based. Virtually all programming languages are open-source – freely available and provided for no recompense. Closer to the base layer of the internet, the entire TCP/IP stack is open, as is BIND, the de facto gold standard for DNS servers.^[2] And whatever your field, chances are, there is a significant open source community in it.
Over the last decade and a bit, I have open-sourced quite a bit of code myself. That’s, to use Mr Hess’s snark, free stuff I produced to, among others, ‘impress’ employers. A few years ago, I attended an interview for the data department of a food retailer. As a ‘show and tell’ piece, I brought them a client for their API that I built and open-sourced over the days preceding the interview.^[3] They were ready to offer me the job right there and then. But it takes patience and faith – patience to understand that rewards for this sort of work are not immediate and faith in one’s own skills to know that they will someday be recognised. That is, of course, not the sole reason – or even the main reason – why I open-source software, but I would lie if I pretended it was not sometimes at the back of my head.
At which point it’s somewhat ironic to see Mr Hess complain about an artist being asked to do something for free (and he wasn’t even approached – this is a public advertisement in a local fishwrap!) while using a software pipeline worth millions that people have built, and simply given away, for free, for the betterment of our species and our shared humanity.
Worse, it’s quite clear that this seems to be an initiative not by Sainsbury’s but rather by a few workers who want slightly nicer surroundings but cannot afford to pay for it. Note that it’s the staff canteen, rather than customer areas, that are to be decorated. At this point, Mr Hess sounds greedier than Sainsbury’s. Who, really, is ‘exploiting’ whom here?
In my business life, I would estimate the return I get from work done free of charge at 2-300% long term. That includes, for the avoidance of doubt, people for whom I’ve done work who ended up not paying me anything at all ever. I’m not sure how it works in comedy, but in the real world, occasionally doing something for someone else without demanding recompense is not only lucrative, it’s also beneficial in other ways:

• It builds connections because it personalises a business relationship.
• It builds character because it teaches the value of selflessness.
• And it’s fun. Frankly, the best times I’ve had during my working career usually involved unpaid engagements, free-of-charge investments of time, open-source contributions or volunteer work.

The sad fact is that many, like Mr Hess, confuse righteous indignation about those who seek to profit off ‘young artists’ by exploiting them with the terrific, horrific, scary prospect of doing something for free just once in a blue moon.
Fortunately, there are plenty of young artists eager to show their skills who either have more business acumen than Mr Hess or more common sense than to publicly snub their noses at the fearsome prospect of actually doing something they are [supposed to be] enjoying for free. As such, I doubt that the Camden Sainsbury’s canteen will go undecorated.
Of the 800 or so retweets, I see few who would heed a word of wisdom, as I see the retweets are awash with remarks that are various degrees of confused, irate or just full of creative smuggity smugness), but for the rest, I’d venture the following word of wisdom:^[4]

If you want to make a million dollars, you’ve got to first make a million people happy.

The much-envied wealth of Silicon Valley did not happen because they greedily demanded an hourly rate for every line of code they ever produces. It happened because of the realisation that we all are but dwarfs on the shoulders of giants, and ultimately our lives are going to be made not by what we secret away but by what others share to lift us up, and what we share to lift up others with.

You are the light of the world. A city seated on a mountain cannot be hid. Neither do men light a candle and put it under a bushel, but upon a candlestick, that it may shine to all that are in the house. So let your light shine before men, that they may see your good works, and glorify your Father who is in heaven.

– Matthew 5:14-16