Usually, I tell people not to do free work.
It’s especially important if you’re a programmer, designer, or writer and the value of your work isn’t as obvious as what someone might assign to a pair of new shoes.
But that’s not entirely accurate. Some of the world’s best and most talented creatives do free work, and quite regularly. Free work can be a good way to stretch, to try something new, to take a risk.
Often, where the problems arise in free work are with people who don’t understand or care about what matters to a creative.
This is best summed up in a tongue in cheek price list that graphic designers share every now and then. Basically, if you’re doing free or low pay work, you’d better also have the creative freedom and opportunity to experiment with it.
Someone that doesn’t understand this balance isn’t likely to appreciate your best work, either.
In other words: it’s ok to do free work, as long as it’s on your terms.