Cam'ron -- I Obliterated a Guy's Nuts ... For Only 20 Bucks

Rapper Cam'ron kicked some dude's testicles into the back of his throat Monday night in Vegas ... and it only cost him a reasonable $20.

Here's how it all went down. Cam'ron ran into a ballsy street peddler who was playing let's make a deal -- his sign read, "Kick me in the nuts ... $20."

Cam'ron accepted the gentleman's offer and delivered David Beckham style. The street peddler collapsed in pain, Cam'ron paid his debt and went on his merry way.