You have to go into the right shops to get cheap goods. In Atar usualy things are more expensive than in NKT. But there are shops that have imported good even cheaper then in the capital. strange but true. You just have to enter inside the places you think are more hidden. Usualy groceries stores or supermarkets with lots of addvertising are more expensive and are made for tourist to see and stop. Atar has lots of luxury tourism which can be seen for the great hotels they have and where i didnt stay cos i cant afford, even if i could i dint want to so... ha, so conclusion, search for cheap shops and ask prices.
you have a strees that has lots of car parts. its the mecanical district of Atar. You can get really cheap things like car oil 2 litres for 3 euros... wow yes its true, and some other part like I did to fix my oil problem.
What to buy: car parts
What to pay: cheap cheap
This is on the main square of Atar. You have a shop with things from Senegal. Atar has lots of people from Senegal that come to Mauritania to make business and escape the lack of employment foung in Senegal. When they arrive in Mauritania they realize its even worse and that hings are even more expensive. They cant come back home, they have to stick to Mauritania because if they come back home empty ahnded their family will kick them out of home saying you're a looser that went abroad and didnt bring a thing or money back home. Thats a big problem with emigrants here in west africa.
This type of markets are very popular in Atar. You can find many kinds of people here. From moors to black people from senegal which have lots of businesses here in Atar. Commerce is very imporatnt here and along with tourism, one of the only ways to survive since its very far away from everything.
What to buy: On this markets you can get really nice fruit, bread and vegetables. You can also buy some handicraft which can get also cheap depending on how much time you're willing to spend arguing with the person tying to sell you a specific object.
What to pay: depends on you baby
you can search for everything in Atar. Food, clothes car parts all you need. You'll find hundreds of streets shgops like this inside the town of Atar.