All sorts of people sell dagga. Because dagga is often used in combination with other drugs, vendors of other drugs may also sell dagga. Known users may also sell the drug. Sales of matchboxes or paper wraps of dagga often take place on street corners. People loitering on corners and approaching passing cars should be questioned.
As with all drugs, the package of dagga is often hidden in nearby debris, rather than on the person of the vendor. Suspects should be watched prior to approaching to determine the location of their stash. Dagga is often sold out of private residences. Households with a lot of short-term visitors should be monitored. Many of these residences will sell to anyone, so buy and bust operations can be executed easily. Strictly follow protocol in attempting any such operation. These buildings are also subject to asset forfeiture. Coordinate these operations with the Asset Forfeiture Unit of the National Prosecuting Authority.
Dagga is also often sold out of petrol stations, where it is less easy to spot unusual behaviour. These stations are also subject to forfeiture, although the interests of justice may preclude seizure where the ownership has not been given notice.
Source: http://www.issafrica.org/pubs/Other/SADrugHBSep04/IIIC.pdf