One of the fun things about GTA IV, is that a player can customize Niko’s appearance in anyway that they wish. This is done by visiting any of the clothes shops in Liberty City. There are three stores that Niko can purchase clothing from: Modo, the Russian Shop and Perseus. If you kill the store clerks, you will not be able to buy clothes. Firing a weapon inside clothing shops may trigger the robbery alarm and give you a warrant level.
Russian Shop: Generally inexpensive clothing for a casual look, this is the first shop that Niko encounters. Items you can buy here include: track pants, jeans, sun glasses, fatigues, sneakers, boots, leather jackets, hinterland coats, flight jackets, spyde track tops, and a Russian hat.
Modo: Sells: chinos, blue jeans, striped shirts, moccasins, golf jackets, ski jackets, brown knits, silk shirts, and tennis shoes.
Perseus: Sells expensive clothing such as suits. You will need to buy a suit eventually as a requirement for some missions. They sell: expresso slacks, carbon suit slacks, Perseus charcoal suit and floral shirt, double breasted jacket in ebony and turtle neck with charcoal pants, loafers, perseus obsidian suits, Perseus charcoal suits, and the slate suit.