Rudy is a character that first appears in Stick RPG, and is later seen in Stick RPG 2, much like Skater Punk or Homeless Harold. It is not confirmed that he had returned in the second game, but it is theorized and is almost certain. In the first game, he paces back and forth between the Convenience Store and the Pawn Shop. He will sell you cocaine at $400 a gram.
Theories on his appearance in Stick RPG 2
It is thought that he returned in Stick RPG 2 named "Rudy" to sell you fake ID's outside the 11-Seven; judging by the color of his head, what he sells and where he sells it in this game, it is very reminiscent of the character in the first game and is often said to be the same character. There have also been theories that his character was replaced by Zev, the stick that gives you a job as a drug-dealer, but the first theory seems to make more sense.