Playing for exposure is ok, if it balances with actual exposure. If you’re first on, and there’s no one there what’s the point of ‘exposure’ to whom. In this scenario, make sure the doors are at least one hour before you go on. You can negotiate anything, protect your art, just because you’re smaller or starting out, doesn’t mean you have to accept a shitty live experience. But always ask for your costs. If the show didn’t sell well, chances are the promoter lost their shirt too.