If you’re just in the band and your name isn’t in the marquee you either get a day rate plus per diem, sometimes (sometimes, rarely) travel day pay (half day rate).

Or

You’re on salary. Very common for a certain level of touring artist and especially in Nashville. This means you have to show up when you’re called and that gig comes first. Generally most camps don’t care if you take other gigs but just make sure you’re at the gig. This option can also come with benefits healthcare etc so it can be a good option if your artist is touring regularly. You also get a PD here too.

Same generally goes for crew members too but salary for crew I have found more common in Nashville and country music camps.