If sacred temples and shrines are the soul of Kathmandu then the markets are its blood. They nourish and deliver life to every district of the city. Streets come to live around 5:30am every day. Buyers, merchants, occasional beggars are caught in never-ending dance of bargaining, purchasing, exchanging of money and goods.
Forget about brands, an item has only 2 criteria: actual quality of the product and how well a seller can push it to you. Latter usually dominates the former. One may feel vulnerable amidst all this but I suggest just to relax and soak in the atmosphere of human interactions, smells, sounds and the temporary nature of it all.