Most of the time when I take photos of street musicians, they're happy to pose. Only once in a while do musicians stop what they're doing, implying that they should be paid for their photograph.
Generally, the good musicians do all right. People drop a few bucks in an open bag or hat for talented performers, or those who look obviously in need.
One of my cousins visited New York years ago and played his guitar on the sidewalk. He got some decent money from it, though he might have gotten the contributions because he was a teenager.
Next time I'll have to ask the performer what they generally get each day. I'm curious!
Related posts: On Music and Elephants, Underground, Acrobatics Below 34th Street and Pulling Strings on the Subway Platform.