Bubbles and Johnny are now trying to buy drugs. This is awfully hard to do, on account of them spending their radiator-and-pipe money on new pants. And wouldn't you know it, they found the one drug dealer in Baltimore who's not susceptible to their "I will gladly pay you Tuesday for two hits of heroin today" gambit. Instead, they'll just have to buy one hit with their remaining cash and split the score between them. The affecting thing about this scene for me is not the depths of degradation suffered by Bubbles and Johnny, but rather that the underage dealer is an asthmatic who's puffing on an inhaler between sales. You have an eye for the crushing detail, David Simon.