The “bottom line” is a necessary evil; the band has to make as much as it spends. If you’re looking to make easy money, sell stuff on Ebay.
Once you write off the expenses and add up the hours, most musicians don’t make minimum wage. That’s not why we do it.
That being said, everyone likes to be appreciated and everyone wants to be treated fairly. If you’re solo, fine; go balance your check book. If you play in a band that gets paid for a gig, you need to have the money worked out ahead of time.
Every band is different. Some have a band fund that is used to pay for an upcoming CD or to produce merchandise or for whatever the band decides. I know one band that had a buy in; they owned the PA, trailer and van as a business. If a member wanted to quit, they had to help find a replacement who could afford to buy in so the retiring member could recoup their investment. If the band wanted to replace a member, they had to buy back that members share.
Over complicated for my taste. My band, Caribbean Blues, subtracts group expenses for the gig (usually PA rental) and splits the rest. This is our agreement, everyone knows going in what the deal is. After the gig, there are no surprises about the pay.
Whatever way you figure out to deal with your bands money, stick to it. Plan for contingencies. Being screwed by the patron occasionally happens, but also plan for being tipped a little extra. Emotions can run high after a good show; work it out ahead of time and there’s less chance of an argument. If you play good music with people who are solid craftsmen and artists, that’s your treasure, no matter the net on the gig.