Mercato Centrale - Within the San Lorenzo street market, you'll find the indoor Mercato Centrale. The Mercato Centrale is very much a farmer's market. Hailing back to a day when supermarkets and hypermarkets were unknown and farmers brought their own goods to market to sell themselves, the Mercato Centrale has an embarrassment of riches in produce, breads, meats, cheeses, and cured olives. You'll find plenty of unique Florentine foods and wines you can take home with you, and you may bump into some of the local restauranteurs shopping here as well. Browsing through the stalls here is delightful, and when you're tired, you can walk downstairs for lunch or coffee at one of the many little cafes and restaurants. The proprietors will often let you try a sample of their foods if you just ask, especially if you're clearly there to buy.
Mercato di Sant’ Ambrogio - The Sant Ambroglio Market is smaller than the Mercato Centrale, but is along the same lines: fresh produce, meats, wines, pressed olives and fresh olive oil. You'll find excellent dried fish and pasta here as well. The Mercato Centrale is in a gigantic indoor warehouse-style building; while the Sant Ambroglio market is also indoors, it has a much more authentic Old World feel to it than Mercato Centrale. In addition to the food vendors indoors, you'll find lots of clothing and other household goods being sold outdoors in the street market adjacent.
Mercato delle Cascine - The Cascine Market is not a permanent market, unlike the others; it runs only on Tuesday from 8 am to 2 pm. However, it is also the largest of Florence's markets, with the widest variety of goods. Located in the Cascine Park (entered at Piazza Vittorio Veneto on the west side of Florence), this market sells everything you can imagine: fine wines and cheeses, fresh produce and other farm goods from the Tuscan countryside, clothing and shoes from Pierre Cardin, Armani, Gucci, and many of the other Italian designers who maintain factories nearby, and nearly anything you might wish to bring home from Florence. If you can go on Tuesday, this market is worth the trip. Save your souvenir money for when you get here.