If you've ever done any artwork, chances are you've gotten praise for it. You may have even gotten lots of "likes" in social media. You may have gotten it published in the newspaper with your name, or in a newsletter. People give a lot of things to artists, but unlike just about any other occupation in the world, most people don't expect to pay them.
No, I'm not pointing fingers, I understand. I started drawing when I was a little kid, and I was happy to hear the praise, to see the attention that it drew to me. I loved to draw, and I still do. I made friends in school by drawing cartoons. It was a way for me to try to break out of my shyness. But I had a future of doing art as a living, inspired by my High School art teacher. He was brilliant. He was not only good at what he did, which was teaching art, and drawing and sculpture, he gave tips on how to turn your art into your livelihood. I can still remember him tell us that if someone complimented your drawing, that you should offer it to them, in exchange for something else. That was my first first lesson in commercial art. So I drew cartoons just for fun, and to entertain my friends, but I also accepted things in exchange, maybe a candy bar. Sometimes I would ask someone to do a drawing for me in exchange. I liked the idea of exchange.
When I started teaching, back in the '90s, I included advice on how to make your art commercial. For some people, it's unthinkable to sully themselves by accepting mere money for their genius, but I guess I've never been a genius. I accept money. In fact I expect it. If someone wants me to, for example, design a logo, I ask for money. If they won't give me money, I won't design a logo. Yes, people often ask me to design a logo for free, and when I ask for money, they suddenly decide to go elsewhere, probably to ask another artist to work for free.
If you've been asking artists to work for free, it's understandable, a lot of people do it. It doesn't even seem to strike people as odd, the same way that you wouldn't ask someone to mow your lawn for free. Or maybe asking someone to mow your lawn, and you'd look at it, and decide how much to pay them, if anything. Or tell them that other people would see how great of job was done on the lawn, and the exposure would be the payment. Do you follow me here? It's kinda silly when you look at it that way.
I've always been asked to do artwork for free. It doesn't even seem to embarrass the people who ask me, I guess it's just part of being an artist. So if someone is asking you to do something for free, then I'm afraid that's what they think your artwork is worth - nothing. But don't get insulted, just smile and walk away. Or give them a quote. If they think your artwork is worth it, they'll pay you. If not, they won't, simple as that.