In my quick search I found sale prices for a 200 watt panel at $1,050(normally $1,900). Considering that those are peak ratings lets assume 75% (I'm sure beyond generous) and 14 hours of sun a day (again beyond generous) and what you have is 2,100 watts for each day. This is enough to power one 85 watt bulb for the day. The electricity would have cost you ~$0.20 from the grid.
So our "investment" should be in the black in about 15 years assuming no performance degradation and free installation.......26 years if we miss the sale
