Every Saturday morning there's a local market held in Placa del Pins. In nearby Capdepera they hold theirs on a Wednesday morning. You'll often see the same traders at both events so range of goods in one market is sometimes the exact same as the other.
Having said that, Placa del Pins market is a lively event where you can pick up some great bargains and get real taste of local culture. It's well worth checking out.