These guys don’t sell stuff on the side of the road, they sell stuff IN the road. And these are really, really busy roads.
In some places (like Accra, Ghana), I’ve heard the men are independent salesmen. They hit up a warehouse in the early morning and buy a bunch of whatever they think they can sell in the road. In other cities (like Abidjan) they are often employees of a wholesaler. They are given goods to sell from an employer who pays them a small amount.
Watch the video and you’ll get an idea of how dangerous the work is. It is pretty terrifying with cars and trucks zipping by while the men try to hawk their goods to those stopped at the red lights.