Although Cairo has its fair share of shopping centres where you can buy pretty much anything you want, the real shopping in Cairo is done in the many Bazaars and souks, particularly the Khan-an-Kahlili market in Islamic Cairo - the oldest part of the modern city.
The outer fringes of stalls are the place to pick up the more touristy goods, shisha pipes, cuddly camels, and models of pyramids, but in the interior, you can find locally crafted treasures including copperware, which represent excellent value for money.
Jewellery is also a good buy in Cairo, although it can be a struggle to find items that aren't too gaudy to actually consider wearing. In the Perfume Bazaar part of the main market, you can get pure essential oils at low prices, and you will often see buyers for major perfume companies bartering bulk discounts.
Remember that in Cairo you are expected to haggle, and most of the traders will speak English to you. If you see any "genuine" antiquities on sale, then be aware that it is illegal to export them without a license, and the chances are that they are no older than a sandwich.