Since Macau is a duty free city, so these world brand good are cheap here. Close to Chinese New Year, these department stores in Macau do have great sale. You could go to the shopping center in Venetian Hotel and the New Yaohan. This is not a large city, so you could go to other parts easily by city-bus or these hotel's free bus. No need to participate in any tour.
You could change money once arrive at Macau Airport. In downtown area and hotels, exchange centers could be find easily.