We, too, have a sliding scale. My wife and I do Cowboy-Western music, poetry, storytelling. Sometimes we are a featured attraction, sometimes we are musical wallpaper. We try to get $300 for a three-hour gig. We usually work acoustic so we ask another $50 to bring a sound system. We ask another $50 if we have to travel more than an hour to get to the gig. Local schools can have us for whatever they can offer, same with libraries, and retirement homes. Don't work too cheap. We find people respect us in relation to how much they are paying us. If you work for nothing, too often the people who booked you will treat you like they are paying you what you are worth.
Claire, Greetings from the Verde Valley.
Good Luck Harpy Trails