I play guitar solo and with a band.
A few choice gigs really add up, especially when I don't have to split with a drummer. I do solo guitar... sort of a spaghetti western mix of old jazz standards, surf classics, cowboy/rockabilly stuff. Folks eat it up. A local art gallery calls me up and it's... i hope you're sitting down.... $400 for an hour of work, sometimes the drummer gets half. Playing oldies at senior centers was pretty lucrative in college too. You have a good time and make people happy. Granted I have to lug all my stuff over there and have it set up an hour before the crowd arrives, but I'm mostly just drinking free cheap wine and stuffing my face with free cheese during that time. I would never buy any of the paintings, ever. But the people there to buy art can tip too!
I busk (play on the street) and if you get the right person with the right tune, you'll get a $20 tip. For playing guitar on the street, which I'd be doing at home anyways.
-Davey Dinner