I need some help and suggestions

So I have been talking with some people in a group chat about food and they have asked me if I would smoke a brisket for an event next month. I am fine doing it and I think I could do it well but I'm just not sure on how much I should charge. I've told them that if I am supplying the meat that it would be the price + cost of meat and that they would pick it up once it is done. They said they r fine with that and that it sounds good but I'm not sure how much I should charge for doing it. I did smoke some meat for a friend for a holiday but I just charged $20 plus price of meat and I was planning already planning to be smoking something at the time so it was only a little more work to smoke the meat for my friend before I did mine. This time I don't have plans to smoke so I would be setting it all up just to do this smoke and I don't want to ask to much but I don't want to charge to little. Has anyone had any experience with this and know what a fair price would be to charge.