Almost every "semt" (section of Istanbul) has a bazaar once during the week, and all you have to do is ask around to find out what day the local bazaar is. The two largest local bazaars, however, are the Salý Pazar (The Tuesday Bazaar) and the Ulus Pazar (The People's Bazaar). The Salý Pazar is held, surprisingly, every Tuesday in Kadýköy, on the Asian side. To get there take the ferry from Eminönü. This is Istanbul's largest bazaar and features everything from local foods, (nuts, fruits, vegetables), clothes, tapes, and cds. You can find almost anything here, and for very cheap.

The Ulus Pazar is held every Thursday in Arnavutköy, on the European side, before Bebek. It's the largest bazaar on the European side, and features much of the same stuff as the Salý Pazar, and because it's on the European side, easier to get to - just take any of the buses headed towards Sariyer, or take a taxi.

Besides these two bazaars, there's also a nice one in RumeliHisarý, and even a small one in SultanAhmet, by the Sultan Hostel. If you really want to experience the wildness of a real living bazaar, and get a picture of what Kapalýçarþý might have been like 400 years ago, head to these other bazaars - you might even find something nice to pick up.