So my band might be playing at a stranger's birthday party in one week's time. He heard us jamming when he was walking by, so he stopped by and asked if we'd play at his party a couple streets over. He was in a rush so there wasn't time to work out too many details, but we told him we were probably down for it and gave him my phone number. As for how long we're playing, he said we could take as many breaks as we want as long as we've sporadically got music going throughout the night. He hasn't called yet, but when he does call, what's a fair price to ask of him? We don't expect a humongous sum, but if he expects us to play for him for absolutely no money, he can forget about it. The gig's probably going to be several hours long with plenty of breaks in between. So how much money should we ask for?