The main purpose is of course to make a good bargain. Some people start their shopping already at the airport before the departure. After that, maybe you get tempted to order from the list, during your flight down, which you get delivered on the journey back. Of course this is very easy and comfortable. How to spend money is your business, but here you can get some good advice.
Salesmen love pale tourists.
Instead, take it slowly and look around, when you make your choice. Decide first what you want to buy and find out what the price is at home. This is specially good if you are to buy a camera or other electrical goods, a watch or perfume of well known brands. These guys are easy to avoid if you want, but if you like to haggle about the price you have got your chance here. You also get offers to buy tablecloth from female salespeople.