Concierge.com's insider take:
In the alleys north of Jemaa El Fna, you'll find Marrakesh's souks. The sheer number of shops is overwhelming, although many offer the same non-essential wares, particularly babouches (canary-yellow slippers, from about $3), djellabas (embroidered gowns, from $11), and etched brass platters the size of manhole covers (from $30). Every section of the souk has a specialty, from spices and ironwork to the ingredients for casting magic spells. Areas worth seeking out include the Criée Berbère, a knot of dimly lit, roofed passageways (once a slave market) that's the center of the carpet trade; and the Kissaria, a ladder of arrow-straight, shoulder-width alleys lined with stalls specializing in cotton cloth, clothing, kaftans, and blankets. The most photogenic is the Souk des Teinturiers, or dyers' souk, which dazzles with drying sheafs of colored wool. The shops nearby major in pottery, lanterns, and metalwork.
The staff at your hotel will most likely try to push a guide on you, but you don't really need one. Hassle from overeager salesmen has been stifled by government crackdowns, and while the alleys are winding, the Medina isn't that big, making it almost impossible to get really lost. (If you do lose your way, ask a local to help set you back on the right track.) And as for guides securing cheaper prices, forget itany savings made are more than gobbled up by their own commissions and kickbacks. Do remember that bargaining is a way of life here. To avoid getting ripped off, first get a good idea of what's a fair price for everything from pottery to carpets at Ensemble Artisanal, a state-sponsored store with fixed prices at the edge of the Medina on Avenue Mohammed V (212-24-38-67-58). When you find something you like, start at one-third the offered price and walk away when you've hit your limit.
Souks are generally open daily 9 am to 7 pm, except for Friday mornings.