Black, 21, whose real name is Bill Kapri, was with three other men trying to get into the US from Canada Wednesday when authorities held them at the border for drug and weapon possession.
The rapper, who was at the wheel of the Cadillac Escalade, was found with marijuana, and officers discovered a Glock 9 mm pistol that he did not declare inside the vehicle.
He was charged with third-degree criminal possession of a weapon and unlawful possession of marijuana, authorities said.
He was taken to the Niagara County Jail, where bail was set at $40,000 or $20,000 cash, WKBW Buffalo reported.
Black was released on Thursday and used the wad of Benjamins as a shield from TV cameras and other bystanders who tried to talk to him, video shot by the station shows.