Mangga Dua usually has wholeseller prices, but the trip there from Jakarta Selatan is a long one through traffic. It's also expensive if by taxi and parking a headache if by private vehicle.
MataHari at CITOS mall is already pretty inexpensive for many household items. If you can catch Matahari during one of its several sales, you'll get 20%-30% off easily and sometimes 50% off on many items. During sales, Matahari is very good for prices.
ITC Fatmawati is also good, but I believe you'll have to bargain the prices. D'Best department store - almost across the street from ITC - also has good prices.
So again, unless you're in for a sightseeing trip to Kota, you've got good shopping places in Jaksel. Good luck.