The Grand Bazaar has over 4000 shops, banks, mosques, police stations, fountains, and restaurants. It is the largest bazaar in the world. As you walk in on Kalpakcilarbasi Cad., you will think it's just like a shopping mall. This is only jeweller's row, however. Take a right and dive into the main bazaar area, with shopkeepers nipping at your heels, carpet sellers begging you to have tea with them, etc. After our experience in Moroccan medinas, this seemed pretty tame. The shopkeepers knew when to back down, and the carpet sellers, while persistent, were never threateningly so - even when we teased shopowner after shopowner as we tried to find the perfect carpet.
Almost the entire bazaar is covered, so it's a great place to go if it's raining, or too hot. If you still get too hot, just wander into any carpet shop and they will close the door and turn on the AC, plunging the small room into subarctic temperatures in no time at all.
The shops sell almost everything. What was missing (and what I much preferred about the Moroccan medina) were the craftsmen creating the goods. Nothing is made in the bazaar; it's all imported (sometimes even from Turkey) and just sold here.
Although all the guide books warned us about how hopelessly lost you will certainly get, we found this was totally not the case. Not only were there street signs and tourist information signs up everywhere, but the layout of the city is pretty straightforward, with many landmarks (like the old bazaar) helping to locate you when you get lost. But again, nothing (and I mean nothing) compares to the complexity and confusingness of the market in Fez!
The Grand Bazaar is an easy 10 minute walk up the tram tracks from Sultanahmet. It is another *must see* when visiting Istanbul.
Be prepared to haggle. They expect it. You should never buy something for more than 50% of the original asking price. As the day wears on, sales get better - especially if the shopkeepers have had a bad sales day. After we finally agreed on buying a carpet, we got into a great conversation with the shopkeeper - we talked to him for an hour after closing. It's a great opportunity to meet Turkish people. It was clear to us that their friendliness wasn't just a ploy to get us to buy, as it continued well after the sale, even when we made it clear that we wouldn't be back in Istanbul for a long time, if ever.
Although a lot of deals can be had, a lot of ripoff's can also be had. It's been said that the Grand Bazaar has the best and the worst of Turkish shopping, and I have to agree. Be aware of the prices and set expectations before you enter the bazaar.