A February 2009 report by the Lawrence Berkeley National Laboratory found that the installed costs before tax incentives for residential and commercial photovoltaic systems had fallen to $7.60 per watt from $10.50 per watt in 2007 dollars. The report also found that the costs for silicon PV panels had stalled in 2005, that costs varied widely from state to state and that economies of scale improved for systems larger than 750 kW. All the while, installation costs in Japan and Germany situated themselves well below those in the U.S., introducing the possibility that U.S. installation costs could drop.
Tell me more on the finances $ and wholesale, retail.