The main market in the city, a couple of blocks east of the Plaza de Armas. The market combines a covered hall of meat, fish, cheese, and freshly butchered local produce with a row of cheap cooked-food stalls upstairs. This is the place to try the altiplano staples: trucha (lake trout) grilled or in soup, chairo (mutton-and-vegetable broth), and quinoa cooked half a dozen different ways.
Set lunches (almuerzos corrientes) cost around 10 to 15 soles for soup, a main, and a drink — well under what you'll pay on Jirón Lima for a similar meal. Busiest around noon. Watch your bag in the crush.