Working for free has the biggest stigma on it. And for good reason, because if you don't know how to work for free properly, you can be taken advantage of. When you work for free, you need to try and always put yourself in the best possible position to gain something from the work. Whether you're just putting new work in your portfolio or you're adding to your network, you need to realize that working for free can benefit you, especially early in your career.
These are your projects that you put together. These are the best "work for free" moments. You get the best work possible that fits your style when you do personal projects. Personal projects tell people your style and your style more than anything else. You have full control over everything because in the end these are specifically for you.
TFP / Trade For Print
These are collaborations between you, a model, and sometimes a makeup artist and/or a hair stylist. You get the point. It's not all about you, it's about everyone as a group. Usually these are standard shoots that fit everyone's style that are more like content filler for your Instagram or your portfolio.
This is great, especially when you first start, because it helps you build a rapport with local creatives and gets your work out to everyone else through multiple people sharing it.
Actually working for free/reduced rate
These are the real gambles. You have to be really sure the work that comes from these can lead to either more paid work or for your network. But you are pretty much being used in these situations. Someone has an event or needs photos for something, and you're just there to fulfill the needs of the client.
Why should you even bother? Right? Well it can be beneficial if you play your cards right. I shot headshots in 2015 at Central Connecticut State University. About 60, fully retouched photos for the students who wanted them. All for free as a test drive. Killed it. Everyone loved it. The next year I was back doing it, but I got paid for it. I got paid a good amount for it too! I turned free work into paid work by telling them I would do it free the first time around to show them this is something people would want. I proved myself and it worked.
I also took photos of puppies for the Puppy Bowl just to say I did that. It was a volunteer job, I skipped classes and work for a day to do it, but my photos appeared on dozens of major news outlets where they showcased these puppies for promotions for the Puppy Bowl in 2014. Who can say they got to do that? Not many. It was a good portfolio and resume builder.
The Super Secret 4th Reason
You're just a nice person. Volunteering is a good thing if you have the time and opportunity to do it. Not everyone can afford good photography, but if you have the time to do the job and no reason not to just do it. Now I'm not saying do it for a large corporation. But if a small organization says they can't afford a photographer, but would like someone to come help out. What's the harm in helping out? Your camera gets a larger shutter count? Use a backup camera.
That might sound a little amateur or pushy to say, but a good deed can sometimes go a long way. If someone asks and you say you can't, that's fine. But if someone has an event that lasts a couple hours and they'll feed you good food for a night to take some event photos I don't see too much harm in that. You're just volunteering with your skill.
If you're working for free, you need to find a way to get something out of it. Whether that's just portfolio filler or networking with more people. Even when you're doing it for the super secret 4th reason. You need to find a reason to be there that can make your time worth while. Even if it's just to clear your conscience. Otherwise it's not worth it for you at all.