There are many markets in Dakar, but Kermel is one of my favourites, as it is small, it is recently refurbished and has a lot of street stalls too. Near the petro station there is a fantastic MASKS place, from all Africa.
We were not allowed to leave the trucks, but they would stop (for pictures), and local sellers would come and hawk there wares. The people are colorfully dressed. This woman had dolls.
What to buy: If you like the goods and are willing to pay the price you can get your souveniers delivered without getting out of the truck, but if you wait, I am sure you will find similar goods in a less stressful buying environment.
What to pay: It is hard to negotiate while trapped in a truck with a bunch of other tourists. So if you buy here you will pay way too much.
The Picture can not do this justice, as this building went on for quite a while with auto parts on the roof in the building spilling out of doorways in the yard. It was quite a sight.
What to buy: If you need parts for your vehicle and you can't find it here. I guess that you are out of luck.
In case you have a craving for french cheese, wine, etc., the french supermarket chain Casino Supermarché has also a shop in the center of Dakar.
What to pay: Prices are about the same then in France