Their illicit 'business' thrives largely because people - mainly travellers - detest formalities, queues and commission charges at banks.
The foreign exchange trade is mainly in the hands of foreigners of Shona stock and the Zezuru - their ethnic cousins in Botswana.
This is an 'underground' operation with a difference - it is an open-air 'affaire' in which the traders almost solicit for business from passers-by. Yet they have to be cagey enough not to approach the wrong person - plainclothes police, perhaps - who may be out to ensnare them.
Once the selection is done, the exchange is quick and hush-hush, yet there is a whirring din that characterises this racket.
The market could not have been located at a better place; the bus terminus is next to the train station, and regular customers are mostly travellers between Botswana and Zimbabwe who go by bus or board the celebrated train to Bulawayo.
Apparently, Mmmegi approaches were not sufficiently sly. Our first contact was a woman who runs a public phone. Even as we were present, she sent off a cryptic message to the racketeers who scampered in different directions.
It was clear that their solidarity was not about to be broken by a snoopy reporter.
As the adage goes, the creed in certain professions is to be 'as thick as thieves'.
But after a little persuasion, the woman at the phone acknowledged that the women in the white dresses were also forex dealers.
"Almost all these people here sell money for money. Try the Zezurus," she said.
The reference to "the women in the white dresses" identifies the Zezuru, a Shona clan from whom Zimbabwean President Robert Mugabe comes.
Ironically, the manner of dress of Zezuru women signifies a religious order. However, those who run the black market see no iniquity or hypocrisy in their illegal practice.
Superintendent Mokuedi Mphathi of Francistown Police Station told Mmegi later that police are aware of the illegal activities at the bus station.
"We have arrested people and charged them," he said, adding that they levy a fine of P1000 on culprits.
