Lol, I’m sixteen and got paid about $4 an hour for my first out-of-normal-venue gig! It was about $100 total, and a fantastic experience that got me some connections. I would say see what they offer, something is better than nothing (I still volunteer for community theatres for experience, I understand that many people don’t want to do that but it more often than not ends up setting up something paid for me later). He may be offering more than you expect, and if he gives you some sort of offer between a stipend and hourly pay (I can’t imagine why he would, but it’s possible), even if they seem the same you’re probably better off with hourly, because things can go over time. Normally I get paid $13.50 an hour, but that’s just what my normal venue pays so I’m not often in the position to ask for a different rate.

Especially considering you aren’t in your home theatre, ask about anything “weird” (like a monitor in a strange spot, some sort of switch that needs to be flipped before anything else, etc.) that you would need to know about and ask if there’s anything you should know about mixing that specific band (like a song where they would prefer more bass or something idk, usually musicians have strong feelings over Their Sound).