Don't work for exposure, and don't even work for low rates, either.
In the past, I was contacted by a company looking for work for hire writing, as if they really wanted my work specifically, but as I got into it, it suddenly switched and turned into an audition where I had to develop my own story from the ground up. And then, of course, when I already put weeks of pre-work just so they'd give me the contract, they offered 2 cents per word I lost it. They gave that "but it's exposure" line, like somehow that will make it worth it to get paid slave wages for hundreds of hours of work and not even keep any rights.
Exposure sure is important when you are breaking in, and I'm all willing to get paid lower amounts in order to show off my work to more people. But not THAT low. And certainly not for free.