Depending on what you're looking for, you've either come to the end of the Earth or its absolute center. Bedouin handicrafts, antiques, simple silver jewelry, and embroidered cloths are really what it's all about here. Though you can also find some good deals on attractive carpets, they're nothing like what's available in Damascus or Istanbul.
Keep in mind that in Cairo haggling is the norm. Most of places that I recommend are, by Cairo standards, quite high end and offer fixed prices. In the shops and stalls of Khan al Khalili or Kheimeya, however, there is simply no such thing as a fixed price, and you should expect to be able to take 20% to 25% off the asking price with a little argument.
Expect stores to open around 10am and stay open at least until 7 or 8pm. Many stores still close for lunch between about 1 and 3pm, however.
Food & Liquor -- Cairo is dotted with convenience stores (ba'ala) where you can pick up an amazing range of items from bottled water to fresh batteries to basic groceries.
Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.