The farmers' market, Mercado dos Lavradores, in the old town is a place most tourists come to visit. It's worth going to as you will find the most amazing selection of exotic and colorful fruits, but keep in mind that buying them will make you poor. It's said that it's the local mafia that runs this market, so that's why prices are so inflated. Generally though it is only the fruits that are overpriced. Everything else including the fish market are not too pricey. The market doesn't have any depth in terms of the Madeira culture, so it's not overly interesting or spectacular, but still worth a visit. Generally you wouldn't spend more than 15-20 minutes here.