Sarojini, Janpath, Lajpath Market.
Street style store maybe or sarojini
You can check out Yashwant Place or even MKT!
@Aditya has already given many options. Apart from that you can also visit Sarojni market, chor bazar.
Try Flipkart you can get 1 month return facility become the ones you would get for road side market may not hold even one month.
Out side Palika bazaar, Janpath market, Karol bhag are some options you might find.