You can buy anything you need at this place, from toiletries to food and drinks, to dishes, to small appliances, and you can find these stores in most French cities and towns. This one that we went to often was located near the University de Belle Beille and outside of the centre ville so it was convenient for us to stop here after class before we caught the bus back to the dorm. To find more stores like this here and anywhere in France go here
What to buy: Groceries and toiletries are cheap here so stock up.
What to pay: Like I said prices are cheap, 1.5 liter bottled waters for example were as cheap as 27 centimes.
Every Wednesday they would have an open air market on one of the city streets...I really wish I could tell you where to look for this place. I didn't have any of my bearings straight when we visited this place early in the trip so I have no idea where it was set up and we never went back...but it was great. We saw everything there, sharks on display at the seafood stand, French pastries, whole rabbits, flowers. And it was just fun to watch the locals doing their thing and shopping. All new to a bunch of Americans who are used to buying everything in the grocery store.
What to buy: Get some mille feuille at one of the pastry shops.
What to pay: Cheap!