Milan is a place where you can hardly find any sale or discount.
But I have some suggestions. You may find some jeans shop those are not famous brands but they are good looking and they are made in Italy.
Also, you may buy some famous brands in Milan, a little bit cheaper than Hong Kong.
However, you need to be very careful as Milan is a little bit like ShenZhen, you will find beggars in underground, African people may sell accessories to you on streets. It's quite horrible.