I lived in Salvador for roughly 6 months and from an insiders opinion Mercado Modello is a great place to visit. You get a great exposure to a lot of the culture of Bahia. Generally speaking everyone you meet is friendly and respectful. While you will see many similar items at several shops don't think you've seen everything. If available check out some Capoeira it's amazing. As a precaution almost everything is overpriced, especially if you look foreign or well off. Be respectful while talking down a price also if you buy multiple of an item they are willing to drop the price. While your there check out the rest of pelourinho and if you have time check out Farol da barra.