This is a dilemma that has concerned me ever since one of my friends dropped out of university, bought a fifth unicycle, and learned how to juggle.
How much do people pay buskers/street performers?
You're not technically obliged to give anything, and I generally don't, being a student with potential impending costs in the form of a zillion more years of formal education. However, I saw the very end of a performance (outside the Bank of Canada no less) last week, in which the errant collected, easily, a few hundred dollars from maybe 80 viewers.
I am also convinced that people give to buskers not only because they value the performace, but because they want to support such talent, or don't want to seem a skinflint to their companion(s).
Either way, it'd be nice to see a model for how these people rake it in.