Working for free has a huge stigma attached to it, and for good reason. If you don't know how to work for free properly, you can be taken advantage of and devalue other photographers' work in the process. That's why there are, in my opinion, only 3 reasons to work for free.
Ted Forbes of the popular YouTube channel The Art of Photography just posted …
Whenever somebody asks me if they should take a free job I answer with a resounding, no. Don't do it. Just don't. It should be a hard and fast rule in your book: do not work for free! That said, everybody breaks the rules, especially their own. Case in point, I just came off of a job this past weekend where, you guessed it, I worked for free.
So since me sitting here and lecturing you about why you shouldn't work for free would be a big waste of everybody's time, especially having just taken a free job myself, lets instead go ahead and look at when, perhaps, just maybe, you should at least consider working for free.
Photographer Tony Wu constantly receives requests that ask whether he would be willing to work for free in exchange for "credit" and "exposure". Instead of a lengthy response explaining why he doesn't want to work for free, Wu often leaves the emails unanswered, or worse, ends up sending snippy responses that he later regrets. He recently came up with the idea of writing a generic and informational response that all professional photographers can respond with.