You will need a bra with a firm cup.  It will need to support a LOT of fringe and coins.  I have had good luck at Walmart and Beall's Outlet.  For this demonstraion I will be using two black bras.  I am going to show how to create a "cabaret" style and a "tribal" style belly dance costume top.  It is important to consider if you will be covering the bra with material.  If possible try to find a bra that is already the color(s) you want.  It can be difficult and time-consuming to cover a bra with fabric.  If you will be wearing a vest or choli with the bra then you will not need to worry about the straps or back as they will be hidden.