Where can I shop for knock off products in Seoul?

My Aunt sometimes goes shopping in NamDaeMun market and buys fairly okay quality knock-offs. But sometimes she goes to DongDaeMun market to buy them, really depends on the knock-off brand she wants. Personally, I think NamDaeMun market has a wider range of knock-offs, but DongDaeMun has better quality ones. Hope it helps ^^