An older building was renovated and turned into a mini-mall, with lots of small booths inside. Most of them will probably not interest tourists very much, but the second floor has a nice variety of offerings in the food court.
Not only to great department stores but the commercial centers are everywhere to spend fast food and even get some groceryes to cook in home. May be you can find even local crafts but check fist price. Commercial centers like "Sendero" "La Fe" or "Plaza Mexico" are cheaper than "PLaza La Silla" "PLaza Fiesta San Agustin" or "Galerias"
The Mall on Valle Oriente is really great. There are a lot of great stores that you cannot find in most places in the United States. I love Zara, Bershka... and many more there.
What to pay: Average prices