As others have mentioned, places to stay and/or new girlfriends were among the best "perks" I aquired back in my old busking days.

Various intoxicants were fairly common "tips" in San Francisco in 1907/71/72. The very first day I took my guitar out on the street -- at the insistence of my housemates, who figured I ought to try earning some money if all I was going to do all day was sit around and pick -- I was scared to sing, and stood there quietly fingerpicking for an hour or two until a passing hippie gave me a pill, identifying it as a cap of mescaline and telling me "this is something you can really use."

I would be more reluctant today than I was then to assume it was OK. I figured "why not" and popped it into my mouth.

Not long afterwards, I started singing at the top of my lungs and was well on my way. I took in more money that first day (just less than $100, in 1970 dollars of course) than I would collect in any other single day for the next year or more; I had found my new career path.